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Not what has been reported so far, but my first tests show that reducing the Supply Voltage to an S5 does work.....

Have just taken delivery of a 2nd hand S5 and after some quick initial checks that everything was ok had a quick go at dropping the volts.

First, very early impression, is that things work as expected...

Tested at 125MHz with 9.0V at the connectors.

(Not wanting to tell people how to suck eggs, but perhaps those that are bragging about how much current they can push through a Molex connector, you need to measure the voltage that is actually getting to the board)

Only measured over a 30 Minute period the Hash was 440GH/s (a bit lower than expected, should be 470GH/s . Over the short time the rate was fluctuating quite a lot and needs further investigation)

Current from the supply (not the wall) was 12.1 Amps so 109 Watts

So that gives 109/440 = J/GH 0.248  Smiley

No xxx, HW error a bit higher than I would like to see @ 0.05%

Boots up and starts hashing at 9V, although to be fair it's 10V with no load because of the rubbish leads I am using on the adjustable PSU.

So a lot more tests to run but a better than expected start. Is it my S5, am I lucky, am I doing something wrong? Time and more measurements will tell.

Rich

How did you go about reducing the voltage?

Yes in the last couple of Weeks while getting the best I could from an S3 I read everything I could find on dropping the voltage to an S5 and it did not look too hopeful. So yes I was very surprised at the result. Having let it run a bit longer I think the Hash rate is a bit lower than I reported, closer to 410GH, but still a good result and still running after 3 Hours.

I have a 40 Amp 3-15V variable PSU, not efficient enough for mining, but fine for testing.

Rich

I have tried  a couple of Software reboots and a complete power down and restart at 9V and everything was fine, have not tried starting with the miner completely cold.

As I was not going to have to listen to the noise I adjusted the Supply voltage and clock up a bit for an overnight run. Ran for 8 Hours with 7 HW Errors. Here were the settings.

Frequency 225MHz
Supply Voltage 10.6V
Current from Supply 24.5A
Power 260W
Average Hash 735GH/s
0.353 J/GH

So again about right looking at the BM1384 data sheet.

Will make some more measurements Today, but need also to set to on seeing if I can adjust a Server PSU to a lower voltage?

Rich

Have done a lot more measurements at different frequencies & voltages and have got to say that testing an S5 on the bench at the higher frequencies is horrendous and has being doing my head in...

However at the lower frequencies it's quite bearable. 150MHz, 9.5V, Fan 1920rpm & 32 Deg.  :)

Interesting to compare it to a typical overclocked S3 @ 0.5TH



Rich

If you're interested, I wrote some programs to specifically do power monitoring and tests on the S5 - one program does realtime logging to a CSV file from the Watts Up Pro Meter (1s resolution), the other one runs the S5 through all the clock speeds, from the lowest all the way up to 450, at each clock speed it runs for 15 minutes to let it stabilize.  I have one more app that connects to CGMiner and logs all of it's data (5s resolution), so you can see all of the characteristics and what they do.  The full test takes about 12 hours to run on a machine, but my objective was to be able to build machine profiles, and see what kind of variation I had among my S5's.

Lately I've been focused on the A2's, so haven't given the S5's as much TLC as I normally do... ;)

Monitoring software sounds great, could save a lot of time listening to the S5... Just need an extension to cope with varying the supply voltage.  :)

Rich

How do you want to interact with it?  Right now it's part of a larger program I'm writing, but I could easily make a commandline one that you'd just specify the IP/port and it would just start logging - does that work for you?  It's Windows-based also, FWIW.

Thanks for the offer but at the moment I do not have a PSU that is programmable for voltage. If I can come up with something it would be a nice idea. :) However I would like to try your logging program as would definitely help in the testing and measuring I am doing at the moment.

Rich

Have you seen this:

http://www.electronics-tutorials.ws/blog/variable-voltage-power-supply.html

Might be worth hacking together to give you some more flexibility...

Hi

Thanks for the links. I have a 40A variable, 5 to 15V PSU which is fine for testing except that I have to twiddle a knob.  :) However this PSU is not efficient enough for Mining so I need to set to and see how much I can vary the voltage on one of the Server PSU's that I have. I think they are by far the best value for money, performance & relaibility you can get. If I can do that with a variable resistor somewhere than that can be replaced with a Digital Pot controlled by an Arduino and we then have programmable voltage.  :) Just need to find the time in amongst all the other things i am trying to do...

Rich

I've made a commandline program (Windows, 64bit) to do the logging for you - you can grab it here:

http://www.analogx.com/files/cglog.zip

The usage is pretty straight-forward:

cglog /ip 192.168.3.226 /device "Antminer S5" /file "log.csv" /verbose

For /device you can specify either "Antminer S5" or "A2 Mega", since those are the only two types of miners I have, they're what it supports.  While it's running, it will output this:

1:[PoolUsername][372]
Hash:1059.83  Errors:0  Temp1:54  Temp2:54  Freq:350  Shares:A145/0

The first line is the Pool 1 Username and how long the device has been running - the second line just gives some values that I'm usually interested in when running tests.  The meat and potatoes are in the "log.csv" file, where I basically save most everything:

Date,Time,elapsed,ghs 5s,ghs av,hardware percent,found blocks,total mh,local work,utility,work utility,frequency,fan1,fan2,temp1,temp2,chain_acs1,chain_acs2,p1 getworks,p1 accepted,p1 rejected,p1 discarded,p1 stale,p1 get failures,p1 remote failures,p1 last share time,p1 diff,p1 diff1 shares,p1 difficulty accepted,p1 difficulty rejected,p1 difficulty stale,p1 last share difficulty
2015-08-14,23:32:07,439,1238.65,1133.38,0,0,497528533.0,300347,22.96,15875.86,350,2880,0,54,55,oooooooo oooooooo oooooooo oooooo ,oooooooo oooooooo oooooooo oooooo ,11,168,0,172,0,0,0,0:00:00,512,116152,121854.140625,0.0,0.0,511.992188

It uses the CGMiner JSON interface, so it might work with other miners that run with it.  Once you run it, it will continue running until you hit a key, then it will shutdown and save everything.  It will not erase the file output, it will append to it - so you can run it multiple times and not have to worry about renaming or deleting the csv file.

Anyway, let me know if you run into any issues or have anything you'd like for me to add, or logging data I might have missed.

Thanks very much. I have grabbed it and will give it a go when I get a chance, busy Weekend here as it's my Grandsons Christening. Don't use command lines much these days  :) but I guess it will all come back...

Do I need to set anything in the S5 cgminer for it to accept the command line?
Have you written anything to explore / display the info in the log file?


Rich

heheh, I included a batch file that has examples of the commands, so if you just edit that and double click on it, it should work fine for you - the only thing you'll probably need to do is change the IP address of the machine, then you'll be good to go.


I haven't written anything yet to specifically do that, but I have been working on an app to do updates via SCP of the image I made for the A2 Terminator's, so I could make something that gets it via that.  Is the log that useful for what you're doing?  TBH I haven't even looked through it, although most of the OS hacking I've done so far is just on the A2...

well your info is kind of too good to be true.

How about a few photos and screen shots to prove it?

If your info is true no one needs any new gear other then the s-5.


If you can do this a guy with 100 s-5's would be able to drop his power bill more then 50%

I am stunned your thread has not attracted more interest.

Gotta say if there is one thing about my limited time mining I don't like, it's the lack of trust that there is in this community.... If I wanted to scam people I can just as easy edit some screen shots, but why would I, what's in it for me? I will try and do what you ask for but if you think about it there is nothing that I can post up that will actually prove what I am saying...

Here for what it's worth... is the complete table of measurements I have made.


A couple of notes on the table.
1)They are measured in amps & volts output from the adjustable PSU, so are not At the Wall, you need to add 5-10% dependant on your PSU efficiency.
2) One of my hash boards is prone to dropping out below 9.25 volts so the data at 100Mz is not sustainable, the best efficiency is in practice at 125MHz,

I agree BTW with your comment on lack of interest. I put it down to my newness and most peoples obsession with overclocking....

Rich

Well look at it from my viewpoint.  My power cost is high.


 I can get those .95% efficient buck transformers I linked to you.  they would take my 93% plat and drop it to 88% which is solid gold rating.

If I get 200 watts and 610 gh   for an s-5 it is great.

I could run 2 s-5's at 1210gh  use 400 watts.

I now need to decide do I want to trust you and spend  4 x 15 = 60 dollars for the dc to dc  and 700 for 2 s-5's.

 I am 760 out of pocket if you are wrong.

Now it could be some units do what you claim So I have to hope I get the right version.

So lets say I do.

  the upside is  really quiet s-5's running at .33 or .35 watts a gh.

I have lots of  power supplies. I do not need to buy one.

I just don't feel like doing all this testing  based on your word alone.

No screen shots of a gui really look bad on your part.

Now I have those buck converters listed. 


 Here is what I will do anyone with good long rep here  I will buy 2 converters and drop ship them to you so you can test your s-5 and see if you can get  these good numbers.

2 convertors would give you 150 watts each so your s-5 can run at 10volts at freq 200 and do around 600gh  which would be 200/600 = .333 watts a gh

So here is a screen shot of the two convertors each can go down to 10 volts at 15 amps and supply 150 watts.

so the s-5 will be able to get 300 watts  which can run freq 200   using 206 watts and hashing at 665 according to your graph.


https://i.imgur.com/wede9K6.png

Phil I think you are being a little unfair, I am not asking you to trust me or to go and buy anything, and even if you were to experiment why not just buy one converter?  You are trying to push this along too quickly. So while I work on the proof, a couple of points to ponder on.

1) The data in the BM1380 and BM1382 data sheets, Core Voltage & GH/s and J/GH has been shown to be correct so why doubt what is possible with the BM1384?

2) sidehack has shown similar efficiency is possible.

3) This is not actually that relevant to most people at the moment. It is to me because of my electricity cost 0.943 Pence / KWH (14.7 Cents) This is the pivot point for an S5. At current difficulty and 15 Cents you are best profit wise to run an S5 flat out. If your electricity cost is lower than this then Overclock. If your electricity cost is higher then Underclock.

4) I had expected this to be a long haul and had prepared the following post as an introduction to the project. I then expected to have a string of posts over a period of time explaining my progress, successes and failures.

This was then going to followed with.


However I posted none of this because I switched on the S5 turned the volts down, made some measurements and posted them.


I am now working on why it works however this is hampered by a few things.

1) Most of my effort, in the time I have for mining, has gone it to making a set of measurements to validate what can be achieved

2) I only have a single example of an S5.

3) Working with the string design is not very nice. You do not have a nice common ground and the ability to easily make measurements and to hook the Logic Analyser up to multiple points. You have to be very careful what you are earthed to at any point in time otherwise there will be a big bang....

Finally for what they are worth a couple of pictures.

http://www.slotforum.com/forums/uploads/1439724411/gallery_2150_2322_190862.jpg (http://www.slotforum.com/forums/index.php?autocom=gallery&req=si&img=70546)

Here is cgminer showing the run at 175MHz

http://www.slotforum.com/forums/uploads/1439724411/gallery_2150_2322_546327.jpg (http://www.slotforum.com/forums/index.php?autocom=gallery&req=si&img=70562)

And here is a shot of the PSU on the same run. 10.0V on the PSU but then 9.8V on the meter measured on the board and 17.8 Amps being taken.

Best I can offer at the moment....


BTW testing with those converters has no value at the moment. They will almost certainly be fine with my S5. The key issue is understanding why this works which is what I am going to work on next.

Rich

Thank you


  my reasoning is this .  You may have stumbled on an improvement in :

A) firmware
B) pcb boards

I pushed hard because I wanted you to be correct.

Now that I see photo proof.  I don't mind buying gear to test out your findings.


I am like you in that my power is costly  so for now running s-5's  that do .51 watts a gh does not work well for me.

But if you have discover something that can be duplicated on other s-5's

Even if only a certain pcb with a certain firmware.  You have found a great secret and shared it to the rest of us. For that you did very well by all of us.

Would not it be nice if 20 to 30 percent of s-5's can clock as you claim?



your gui and meters are showing about 180 watts dc  to  get 578 gh   this is   180/578 = 0.311 watts a gh.

I would set up an s-5  right away based on this.

philipma1957, while it's cool you're making the offer, personally I don't think it matters at this point... He's still in the process of testing things out, and has been posting more updates than soliciting anything from anyone.  I don't think there's some immediate rush that would necessitate running out and verifying his results quite yet - and once he's nailed down things, I'll be more than happy to buy the converters myself and test on one of my rigs.  I'd rather see you buy them for him at that point, so the person spending the time figuring things out doesn't have to eat all the costs, instead of just some random guy who verifies his result.

I also think RichBC is spot on with his comment about the obsession primarily being hash rate, and while people get excited about efficiency, when you tell them their 1.1TH would be running doing 400GH, their interest wains.  ;)

And to RichBC, love the work - and welcome to the community, but I think to philipma1957's point, this space is unfortunately filled with scammers and most people have gotten their hopes and dreams smashed against the rocks of reality on more than one occasion on here.  The nice thing is that once you're a known quantity, the community is very supportive and active - look at Sidehack or some of the other hardware threads out there and you'll see what I mean.

Either way, keep up the good work!

I am going to  rescind my offer to ship those converters out.  I am going to order my own s-5 and try to duplicate the op's results.

@ op  what was your firmware and board codes?

I'm totally with you - I would love to run a bunch of my S5's at greater efficiency vs greater speed.   It also means that you'd have a longer lifespan for the device, as difficulty raises you can slow it down and boost up efficiency.  I'm not a huge fan of the step-downs you found, but for testing things out they'd be fine... I think the ultimate solution would be to pick some decent power supply, and reverse engineer it enough the change the 12V output to some alternative fixed amount.

But the big question is probably less about whether or not the device can run for some period of time at a lower voltage - but how stably it does.  In the screenshot you can see he's got some hardware errors - and maybe his S5 has a bunch running normally, but to me that's reminiscent of overclocking - ie; the closer to the edge you get, the more errors you encounter.

The only other thing to consider also would be whether or not to pull the BB/Controller off of this voltage adjusted input - I can't think there's a reason you couldn't run them at 12V and just undervolt the blades.  The BB has a voltage regulator already in it, so it should be pretty tolerant in either case.

Ah, one other thought - are you running the fan off of this?  I notice the RPM is 2040, so one thing that could skew your numbers would be variations in what the fan pulls.  Personally when I do power calcs, I usually put the fans on a separate PSU just so I can focus on the device, and then run the fans at full so I know the worse case fan draw.

Just a comment on these points. The HW errors are sort of deliberate. The S5 seem to very smoothly go from no errors to a few to a lot as you wind the volts down at any given frequency. So for each of the tests I adjusted it to be just into errors as this was an easy way of knowing I was on the edge. In practice you might want to add 0.1V to each of the levels, and they may well be differences between machines and on mine there is definitely a difference between boards of a bout 0.2V.

I think the BB/Controller is absolutely fine at 10V as it's ok at 9V, but definitely on the list of things to check.

I left the fan connected as normal as this seemed a fairer test, and if it was oscillating between 2 speeds took the current at the higher one. At this stage to be honest I was not after the last decimal point of accuracy, this was about does it work....

Rich

Awesome!! 
I needed this, was thinking of a way to put 3 S5's on 1 breaker... just happens I'll need to lower 1 out of 3 to make it happening.
This kind of detailed listing, in this type of business should be given by Bitmain themselves... but some people have equipment, so amen.
Now I can buy more miners and increase my hashing power.... price of Bitcoin right now, the only thing worth spending on in hardware.
With this I'll be able to add an extra 3TH.s for sure, if not 4!!
Now with the S5+ that will push back the release of any new processes, not a bad idea to further invest in used S5's...

Might not be 100% accurate but it's a good rule of thumb to start with.

 78xx and LM317T are both fairly low current limit - 1 AMP for the 78xx series, I think 5 Amps but might be a lot less for the LM317, can't remember for sure since I've not worked with those in a while.

 Both are also VERY inefficient.

 It's possible to use an external pass transistor with them to up the current limit, but you're still dealing with a LINEAR regulator, and therefore VERY INEFFICIENT.


 Finally found my guestimates - in the RBox upgrade thread, not the thread I thought I posted them in.

 S5+ turned out to be a bit more efficient than my 16-per-string guess, but looking back at that guess I think I misfigured a bit - it should have been better efficiency that a stock S5.


 The figures posted for .6 are higher on GH per chip, but not by a lot, and pretty close to dead on for power-per-chip between my guestimate and the "9v" figure posted.
 I don't see ANY reason to doubt the posted "as measured on a S5" numbers, they're right in the ballpark of where they SHOULD be based on the published specs for both the S5 itself AND the BM1384.



 The real trick now is to either figure out how to turn the +12V on a low-cost EFFICIENT power supply down to 9-10V range, or find a higer amperage capability converter that can do 12V to 9-10V range, or find a high amperage PS that is high efficiency in the 9-10V output range.

 Why not split them out a bit, should be able to run 5 easily split between 2 circuits. 2 one one circuit, 2 on the other, 1 split between the 2, without pushing a 15A 117VAC circuit particularly close to it's limits.

the buck step down I linked is 95% and can handle 15ampa at 10 volts.  so 2 for each s-5 is about 30 dollars

doing better then 95% is not going to be easy.  and 95 percent of a 93 percent platinum psu is a 88 percent psu.

my method will work but costs too much its would be 30 bucks an s-5 and add a few more for cables .  so close to 40 an s-5

I am slightly annoyed with these comments, but I guess I am new so have to put up with it...


And that...


I did not stumble on it. I read the data sheets, looked at what sidehack has done and decided to find a way of making an S5 perform at a lower voltage. 

All I have tried to do in this thread is to share the information that I had found, albeit in an incomplete state, not to be taken to task over it's validity.

MarkAz thanks for your support, now let's move on....  :)

I was wishing in some ways that I had just kept this to myself until I had done all the work to understand what the problem was and how to fix it, but thinking on it overnight this project is going to go ahead much quicker with some help.

My best theory at the moment is a simple one, that S5 working at a lower voltage is Hash Board specific, with changes being made in later versions which then make it possible. I am assuming that tests done by others were on earlier versions of the Hash board? They did not add the version to their posts, so I cannot prove that.

I can't afford to go out and buy a version of each of the revisions of the S5 in order to test and prove which versions work at a lower voltage and which do not. So I am collecting all the paper research I have done and my guess at what the problem / key change was, and will share as soon as I have put it all together.

Rich

I'd prefer something that would go AC line -> 9-10V range with 90%+ efficiency, not ignoring your bucks but they are extra bucks.
I'm also not convinced they're good for 15A in a mining setup.


 A couple of the other converters they list mention higher power output with a heatsink upgrade, though. Would have to look into the details.


 Might be worth looking at next summer after the halfing as a way to keep my S5s hashing at a profit for a while longer (don't need them on my SP20E of course), but I'd prefer to figure out how to adjust the voltage down on my existing power supplies.

I have collected together a set of pictures of all the S5 hash board revisions I can find, may or not be complete, but it's enough to be getting on with. Here are the pictures along with my initial comments on the changes. There will at this stage almost certainly be errors & omissions, this has all been done in a quite short period of time.

V1.1   2014-12-03

http://www.slotforum.com/forums/uploads/1439724411/gallery_2150_2322_458290.jpg (http://www.slotforum.com/forums/index.php?autocom=gallery&req=si&img=70649)


First release. Easily identified by the large cleared copper areas.

VDD decoupling components on the front of the board

Only 5 of the 6 possible level shifters placed

16 Pin connector to controller board

PCI-e 6 pin power connectors close together in S3 compatible position

Single oscillator module Y1 on the ground level chip.

Credit to dogie for a decent high res pictures, wish the others were as good.


V1.3   2014-12-15

http://www.slotforum.com/forums/uploads/1439724411/gallery_2150_2322_221557.jpg (http://www.slotforum.com/forums/index.php?autocom=gallery&req=si&img=70657)


Move to 18 pin connector to controller board. (Have not investigated what the additional signals are for?)

PCI-e 6 pin Power connector spacing widened, not S3 case compatible any more.

All 6 level shifters fitted along with additional SMT chip marked G07F. I think this is a SN74LVCG07 Buffer / Driver chip. Possibly / probably associated with the additional data connections from the Controller board?

Single oscillator module Y1 on the ground level chip.



V1.5   2014-12-20

http://www.slotforum.com/forums/uploads/1439724411/gallery_2150_2322_315871.jpg (http://www.slotforum.com/forums/index.php?autocom=gallery&req=si&img=70665)

No immediately obvious difference to V1.3 but have not examined that closely.



V1.7   2014-12-22

http://www.slotforum.com/forums/uploads/1439724411/gallery_2150_2322_182622.jpg (http://www.slotforum.com/forums/index.php?autocom=gallery&req=si&img=70673)

VDD decoupling components moved to reverse of the board. I have assumed they have been moved to the reverse as I do not have a picture of that side of the board.

The cleared copper area on the reverse of the chips is now a clear rectangle. I could guess clearing the way to easily fit a mini heatsink that comes later.



V1.9   2015-01-08

http://www.slotforum.com/forums/uploads/1439724411/gallery_2150_2322_641456.jpg (http://www.slotforum.com/forums/index.php?autocom=gallery&req=si&img=70681)

Board layout changed to make provision for additional oscillator modules. Y1 to Y5. See V1.91 for more info.

Also provision for Oscillator modules on all stages Y1 to Y16.




V1.91   2015-03-28

http://www.slotforum.com/forums/uploads/1439724411/gallery_2150_2322_125853.jpg (http://www.slotforum.com/forums/index.php?autocom=gallery&req=si&img=70689)

Additional oscillator modules Y1 to Y5 fitted. The level shifting chain is broken at each of the points that an additional oscillators are fitted. Each oscillator drives 4 pairs of chips, and the last on in the chain 3 pairs.

Addition. The LDO regulators on all but the last stage are removed. Voltage for the IO & PLL is now taken directly from the Core Voltage of the stage above.
This is a significant change & means that the IO & PLL voltage will track up and down in proportion to the supply voltage. Also it might have been possible (Have not measured) in the earlier boards at lower supply voltages for the LDO, which took it's supply from the core voltage 3 stages up, to drop out of regulation.


V1.91 2015-03-28 (With Mini Heatsinks)

http://www.slotforum.com/forums/uploads/1439724411/gallery_2150_2322_500598.jpg (http://www.slotforum.com/forums/index.php?autocom=gallery&req=si&img=70697)


Another version of V1.91 built with mini heatsinks fitted. Look the same as the ones fitted to S5+, so perhaps a trial? Do not know why they, on all the ones I have seen, did not fit heatsink to U20 & U29?



So there are 2 "big" changes that have taken place. First was on the transition from V1.1 to V1.3.The 6th level shifter was brought into play along with it's Driver Chip. The change from 16 to 18 connections to the Controller Board and the other Controller board changes was also made at this time and may be associated with this?

This could be the key change, but have no way, at the moment, of confirming that. I suspect it is not, but it would still be useful to understand exactly what this change does?

The second change is the one I am putting my money on being the key enabler of lower voltage working. V1.9 of the PCB made provision for additional oscillators, at V1.91 they were fitted.

The Oscillator count goes from 1 to 5 and the oscillator level shifting chain is broken at each of the points that an additional oscillators are fitted. Each oscillator then drives 4 pairs of chips, and the last on in the chain 3 pairs.

This change is consistent with one of sidehack's theory's that some of the signals are not making their way through the chain if the voltage is too low.

There are also pads on the layout for an oscillator for every pair of chips Y1 to Y16. These additional Oscillators have a different pad layout to the fitted ones Y1 to Y5

My S5 is has the V1.91 with heatsinks and can definitely be undervolted as shown in my previous posts. Most of the testing was with the 20150415 Firmware, but over the last few days have been using  20150715 with no noticeable difference.

I want also to take a look at the LDO regulator(s) for the PLL Analog & Digital power. Silly thing is I can only find one. It's either staring me in the face, on the reverse of the board or not there? I am sure that sidehack could put me right here.

If this all works my favoured solution for powering would be a modified Server PSU. They mostly have provision for a small adjustment 11.7V - 12.7V. I think some can be adjusted more than this, perhaps you could jack the sense input up and reduce the voltage? If anyone already has a solution, or wants to take a look that would be great? I am not that keen on the additional complexity, cost & reduction in efficiency of an additional VRM.

More to come but I have now shared everything I know and if anyone else wants to pitch in trying versions or understanding the changes please do so and let us know what you find?

Rich

 so the facts are the early versions tested don't do well at 9 or 10 volts


the newest version did great at 10 volts  even 9.5 volts.

v1.1   2014-12-03
v1.3   2014-12-15
v1.5   2014-12-20
v1.7   2014-12-22
v1.9   2015-01-08



one from below was able to clock low

v1.91 2015-03-28
v1.91 2015-03-28 -With mini heatsinks

so we need the people that tested and got bad results to get back to this thread and let us know what boards they tested.


Like you said it may be multiple units of s-5 can do this.

not just version v1.91

this would let the 'good s-5' run at 650gh 200 watts and with quiet fans.

it may allow  for the s5+ to drop to 6th and use only 2400 watts.

lots of possibilities.

I think I may get an s-5+ and test this out. rather then get an s-5.

P.S. don't be sensitive to my style of writing I have been through a lot on this site and have been pretty blunt.

  I  would think this thread should get interest and it does not get a lot.

 I am making an effort to acquire  some btc and get  the s-5+
I would like to think it can be down clocked to a sane sound /power use via your methods.

If anyone wants to run a test on their S5. Remember you do not need a high current supply to do it. Only connect one of the hash boards to the supply, the one with the 4 pin connector to the control board, this will halve the current needed for the test.

Set the frequency to 125Mhz. You then just need a supply with a voltage between 9.25 & 10 Volts at 6 Amps and that will be good enough to give a strong indication that the tested S5 will or will not support undervolting.

For a quick test you can probably get away with putting two or three 10 Amp Silicon Diodes in series with your 12V supply. You will need to monitor the voltage getting to the hash board when it is hashing to find the exact voltage it is running at.


Rich


Just to add. The most important board to test at this stage is a V1.9. As far as I can see it's identical to V1.91 but without the additional Clock Modules. If this does not Undervolt almost certainly none of the earlier versions will.

your research on this is to be commended.  I really think it would allow some s-5's

v1.9, v1.91  an under clock

I also think it works for the s-5++   if so  the s-5++ becomes a better piece of gear.  For the home miner.

I ordered btc from coinbase it arrives this friday. I will order the s-5++  and test it.

Phil do remember that the S5 is yet to be understood & the S5+ is completely uncharted. You would be hoping that the S5 solution is something like the multiple Clock Modules and that they carried that design through to the S5+

Rich

yeah but if true it makes the  s-5++ worth quite a bit more.

Start out with whatever your power/sound/heat will bear.  Then clock differently as your prices for power change.

In my case power is 16.9 cents in the summer  add more for ac.  Not that I use ac to cool it but it will warm my house a bit   so I am in the 18 cent a kwatt for power right now.

If it works on an s-5+  I can down clock until my winter power rates come in  13 cents minus a 3 cent benefit for the heat. 10 cent power.

It allows me the s-5+ in house.

 If it does not work  I have a place to host it.  I ordered the coins from coinbase  they come on friday.

My gut feeling, For what that's worth,  :) is that it will probably be ok....   You will of course need a lot of amps at the reduced supply voltage, so we will need to crack modifying server PSU's to run at a lower voltage. The good news is that because they have extended the chain length to 16 all of the voltages in the table will be Plus about 0.7V for the same J/GH. So in the order 10V to 11V

Rich

I did some quick math on it.  the step downs I found  cost 15 each    9 boards with 3 connectors = 27 stepdowns at 15 is 405 not acceptable to spend that much.

But to test this I can use  1 board run it at freq 200 get   power numbers.     

With 12 volts each board should use  close to 385 watts at freq 325

Once i see what the one board does at freq 200 (my guess is 237 watts as  200/325 x 385 = 237)


then run the one board with 2 step downs which are rated for 150 + 150 = 300 watts   if I go down to 10 volts  10/12 x 237 = 197.5 watts a board

so the full thing  would be 9 x 197.5= 1777 watts  and hash at   4.75 th      or .375 watts a gh.






If all of the above is true  the s-5+ just got better.

Possible good news on the S5+ design. Have had a look at the low res images of the Hash board front & back and as far as I can see there are multiple clock modules and unless my eyes deceive me I can see the level shifting diode missing from every interstage clock coupling.

So now the IF's  :) IF I am right on this then there is a clock module for every triple, 16 in total. So IF this is what makes the S5 undervolt it may well carry through to the S5+

Rich

Don't let skepticism ruin your mood. I think you'll make a bunch of friends if an affordable mod come out of this. Skepticism is a necessity to keep your sanity, here. Its always like this in public places where money is involved. Anyways;

Its a bit of a shame we can't do this mod for 0.001cent like you can with the S1 soft mod. I'd be interested to test this for fun if i/we find a convenient/dirt cheap way to test it out on separate units. Otherwise for now i'm far from being able to draw a benefit from doing this currently.

Beside maybe making the unit nearly completely silent. Which could make quite a few individual's wives very happy.

I fear i can't really contribute currently, as all i have available is a Multimeter and a 1.91 antminer from the same Batch as you.

I am just being a bit cautious at the moment. Don't want people to blame me if this all comes crashing down. I have another V1.91, without heatsinks coming later Today so will be able to confirm that my first one was not a fluke.

I had first attempt Today at turning down the Volts on one of My Server PSU's an Intel DPS-1200TB A. An excellent Platinum PSU at 12V. No pots to twiddle inside it so I had a go at using the Sense voltage to make an adjustment. Goes up to 13.4V but could only get it down from the standard 12.2V to 12.02V. At that point there seems to a limit built into it.

I feel that to get the best out of the undervolting we are going to have to find a way of adjusting a Server PSU voltage, as any added converter module is going to throw away a lot of the gain. I have a couple of other Server PSU's to try so will see where I get with them?


Rich

yeah the step down bucks came today..

  so lets say they work and really do 15 amps at 10 volts and 95% = All best case numbers!

that is 15 bucks a pcie cable at least 2 per s-5 costly

Putting aside the costs for the moment, I would urge caution in working with the step-down bucks. It seems to me that you'll need to use one buck per PCIe socket. That would only get you 15A for the one socket, and I wonder if that will supply enough current for the blade (i.e. 150W @ 10V). The bigger hazard then might be in thinking that you could use a second buck for the other PCIe socket on the same S5 hashing blade. As I understand the S5 hashing blade, Bitmain cautions you NOT to use two different power supplies (or rails) to the same blade, since it's unlikely they will have exactly the same value on the 12V lines, and the two supplies will "fight" over the result, and it might not end well. If you use two buck's, then you effectively have two different rails going into the same hashing blade, even if they originated from the same power supply.

I am NOT an electrical engineer by trade, and it may well be possible to get the buck voltages close enough that it won't matter. I am certain if you need more than one buck per hashing blade it will be important to get them very close in their voltage.

If you can get somebody like sidehack to weigh in on this and tell me I am full of sh*t, that would be swell. I just didn't want something to get damaged (e.g. an S5 blade, a buck) without considering the possible ramifications of using adjustable step down buck converters.

One thing I have always wondered: Where does the controller get it's power from? One specific hash blade or what? That might also factor into this as well.

Best of luck, Phillip!

Hmm, unless i missed something. Why use 2 connectors? Just 1 connector should be fine?

The second S5 arrived this Afternoon, there is good news not so good news.

Its's a V1.91 but without heatsinks, has the 5 clock modules fitted, but has a different silk screen on the PCB. I have not had the cover off yet to have a close look.

The good news is that it will boot at 125MHz & 9.25V like the first unit. The not so good news is that the HW error rate at those settings runs at about .02% whereas the first one was .0005%, although I did not log it. The error rate itself is however not the main difference. On the first unit there was a smooth and quite rapid transition from a lot of errors, through a few errors, to acceptable / no errors as you inched the voltage up. At the lower voltages it typically spanned 0.25V.

On the 2nd unit I have to increase from 9.25V to 10.0V to get to that acceptable/ error free point. The same characteristic applies at higher frequency / voltage but the additional voltage needed decreases. At 250Mhz it increases from 10.4V to 10.7V. I will look at it more carefully and make proper measurements in the Morning.

So I guess we should not be surprised there are variances, problem now is to find why and can anything be done about it? One thing I will do on both units is to repeat the measurements with just one Hash board connected at a time to see how each of the individual boards compare?

I have this gut feeling that there is a chip in the second unit causing the problem, but if that is the case it will be difficult to find. It is a pity that HW errors are not reported on a per chip basis.  :)

For comparison on the points I have checked Unit 1 & Unit 2


All the above provisional as it's been done rather quickly.



Rich

On the buck converters, as VirosaGITS says and particularly as we are undervolting I think 1 per board would do. However I cannot see myself risking one an an S5 hash board. I also have my doubts if they will meet the efficiency claims. I agree that potentially they are a neat solution, but feel that I / We / Someone will need to find a way of reducing the voltage on a Server PSU, if we are not just going to throw away everything we have gained. As I said I have a couple of different ones here which I will look at when I get time.

The controller board takes it's power from one hash board, definitely some of that comes from the separate 4 pin connector. I am unsure if it also takes any voltages from the 18 Pin connector?

Rich

All i can add to that 1 connector per board thing is that users report running with only 1 connector at stock settings without any problem, as its within the 300w spec per connector i believe.

At least i can say doggie is very vocal about this and if you take a look at the S1 or even S3 to an extent they run at 250w and 220w watt per connector. So an undervolted S5 as per the graph start at that margin and then only go lower.

So unless the connector has some weird mechanic where they don't work because A go up for V to go down, they should be fine since its ultimately lower watt than the max in any case.

they will do the job I have used them before.  I used the 10 amp version and it pushed 9 volts and 93 watts 24/7 for weeks.  I know the 10 amp version works well and it did approach 95% efficiency as it was listed.

the 15 amp version is rated 98%  under ideal conditions..  basically dropping from 12 to 10 or 12 to 9 is not like dropping from 24 to 5 .

Also if you use a fan with them they will even work better.

Since I plan to go down to 9.5-10 volts  and use around 100 -105 watts a rail  I am 106 of 150 which is  under 80%   the safe  24/7/365 is to derate be 20%  so under 120 watts and I will be good to go.

Well that is the good new the bad news is amazon sent me the wrong order today  they sent 1 15 amp piece and a 3 amp piece.

So I am exchanging the  3 amp for a 15 amp piece.

Even if all this works out at 15 bucks a rail it cost too much

30 an s-5

and I think 18 x 15 or 270 for an s-5+  

for now I am dead in the water until I get the second one replaced.

I have this server to test with

http://www.gigampz.com/store/p21/Gigampz_80Plus_Platinum_Efficiency%2C_1200_Watt_Kit.html

Why not run a single board for now?

don't have an s-5 on hand I have coins on order to buy one and freaking bitmaintech sold out the s-5

I will cross that bridge when the coins come on friday from coinbase.

I became interested in this because at .35 watts I can run gear at my summer price rate of 16.9 cents.

All my gear was sold in May  2015 except for sidehack's usb sticks and 1 u2

My point was that the buck converter that Phillip mention was only capable of 15A. At 12V that would be 180W which fit well within the connector limits. IF however, you need more than 15A for the blade, then you would likely need to employ a 2nd buck, which would most naturally use the 2nd PCIe socket. If one buck can support an entire blade, then no issue.  

should do so since he was getting   200 watts and 665 gh on two boards.

My electrical knowledge is decent not great but I think since this all comes from a 1 rail server psu 2 bucks a rail should be okay.  

do not have to go there.  since I can send pull the fuse from each converter replace with a low amp tie both pos and both neg and run just a fan.

no magic smoke and we would be good to  go.

https://i.imgur.com/6xTLb3V.jpg


cooling fan allows for more power handling
https://i.imgur.com/E9m6jFP.jpg

Have been busy this Morning, in amongst all the BM1385 excitement, and have made some progress on the 2nd S5 with V1.91 Hash Board, no heatsinks.

I disconnected in turn each of the Hash Boards and remade some of the measurements. The first board continued to exhibit the long voltage knee between a large number of hardware errors & no errors that I explained Yesterday.

The second board on it's own behaves very much like the first S5 with the heatsinks, in fact it had very good performance, the best I have seen so far. That said I had suspected that one of the boards in the first unit performed better, the figures reflect the performance of the lower performer,  but never checked it out.

So here are some sample measurements from the "good" hash board in the second unit.


Remember this is only 1/2 an S5 so Amps, Watts & GH are half previous tables, other figures can be directly compared.

So not quite up to BM1385 performance but at 150MHz & 9 Volts gives 248GH with a (record breaking) J/GH of 0.269 :) This was with no HW errors and also remember that the Fan & Controller board current is included even though it is driving a single Hash Board. Power is, as in all the other measurements, calculated  from the supply, not at the wall.

So now need to go and understand what is holding back the other Hash Board in the 2nd S5? First examination shows it to be a slightly different board. Both are 1.91 with the 5 Oscillator modules.

The First S5, with heatsinks, both boards are marked V1.91 - GYS0150 - 2015-03-05

The "good board in the second S5 is marked V1.91 - GYS0107 - 2015-03-28

The "less good" board in the second S5 is marked V1.91 - GYS0199 - 22-15

Whether any of the markings are significant I do not know?

I will have to set to and make some measurements, but my gut feel remains that there is a chip which is for some reason under-performing?


Rich

Very well done. I guess it is not possible to check the voltage on a chip by chip basis to see if there's some issue somewhere?

Yes there will be some voltages & signals that can be checked, but not quite ready for that yet as I am still feeling my way round the circuit. Measurements are complicated by the string design with no common ground, with the ground for each pair of BM1384 up the chain being VCC from the previous stage. Also means you cannot just isolate a stage which would be a way of tracking down a problem.

It could be as simple as poor heatsink compound on a chip, but I suspect it will not be that easy. I will fully measure the performance of the 4 hash boards I have, while thinking about how to find differences between the boards. If as I think is the case I have 2 very good hash boards I will put them into a single S5 Module and set it Hashing  :) while I investigate the other two.

I will get there and had expected this to be a tricky process, the surprise was a level of instant success.  :)

Rich

Nice topic. So basically you use a dc converter to drop voltage on the in power of the S5 ??

Nice cant wait to see the final result!  ;D

Edit: will that work ?? http://www.amazon.com/SMAKN%C2%AE-Converter-Power-Supply-Module/dp/B00N3OAV2W

A DC-DC converter is one option and probably the easiest way to drop the voltage as you can use your existing PSU. The cost is the price of the converter and the added inefficiency. A better solution would be able to adjust the voltage of the main PSU down while retaining it's efficiency. Weather that is possible or not I do not know?

Another approach I am considering, but not for the faint hearted, is to patch additional BM1384 chip pairs from another S5 hash board into the string to reduce the voltage on each stage, not very practical to replicate but interesting as a one off.

With 2 S5's, you have 4 hash boards, so you take one third of the 4th board( 5 Chip pairs) and patch them into the other 3 boards increasing the chip pairs from 15 to 20 and so reducing the core voltage on each chip from 0.8V to 0.6v. Easier said than done, but on the list of possibles.

Rich

Edit  :) Yes that would work, a bit expensive & not adjustable. The ones that Phil identified earlier in the thread are probably a better bet.

Lmao. That's a bit crazy. But maybe you could have some fun with that. Let me/us know if you try it. Hopefully the firmware won't mind handling weird hashboards with 40 chips instead of 30. I'm sure some people would be interested in such miner, i would but yeah xD

Phil you can adjust the volt on your ? Can you give us a link to find it?  ;D

Thanks

Edit: could that work https://abra-electronics.com/power-supplies-transformers-adapters/enclosed-switching-ps-circuit-test/psf150-9-ac-dc-power-supply-150w-9vdc-17a-psf150-9.html

valkir, that 9V supply you linked would work - but what's the efficiency of it?

Efficiency is one issue, but you also really need an adjustable supply dependant on what frequency you want to run at. Ideally 9V to 12V, but 9V to 11V would be ok as you can use existing supplies for 12V.

Ok so I guess this one could be better.
http://www.ebay.com/itm/DC-DC-Boost-Converter-Adjustable-Step-Up-Step-Down-Power-Apply-Module-High-Power-/400765676880?var=&hash=item5d4f7eed50

Phil do you have any update ?

I now have   2 of these


http://www.amazon.com/gp/product/B00C9UUFHC?

these should work fine see below

Product Description
Size:15A
Parameters:
Input voltage: 4-32V (36V Max)
Output voltage: 1.2-32V (adjustable,default output 5V)
Min voltage difference: 1V
Output current: 0-15A(10A for long-term work)   with a cooling fan it should be able to do freq 200 at 10 volts   say 110 watts
Input fuse: 15A
Operating temperature: -40°c to +85°c
Working frequency: 150KHz
Conversion efficiency: up to 98%
Module size: 60mm x 51mm x 22mm
Installation: 4x 3mm screws

Application:
1.Its volt convert examples: 12 to 3.3V; 12V to 5V; 24 to 5V; 24V to 12V
2.The board can be used for step-down volt converter such as battery, power supply transformer, DIY adjustable voltage regulated power supply,
24V car laptop power supply, car LED lights power supply,buck volt convert for industrial equipments ,etc

Note:
1.Over-temperature would reduce its output current   may need a fan
2.Without input reverse polarity protection(if need, please install diode at input port)

Package Include:
1x DC Buck Converter


Of course I don't have an s-5  and the s-5 sales are done on bitmaintech.  I have coins to order one. (coinbase sent them today)

Finally did some digging, and found 2 better PS options.

 Both are specified to adjust down to at least 10V, and will probably go somewhat before that (9.0v probably not but 9.5 perhaps).
 Both are fairly efficient (88% ballpark) - not gold but close, as good or better than running a 95% buck that might not handle the power load from a gold ATX PS and tossup with running a 95% buck from a platinum ATX.

https://e4btc.com/sea-sonic-pf-series-sse-3201pf-12
http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2172084_-1

 I wish I could find a US seller for the Seasonic.

 Might need 2 (1 per side) if you don't undervolt a LOT.
 Might get away with one for both sides of an S5 at minimum voltage setting on either of these.


 Jameco showed some lower-price lower-power varients on that second one, a couple of them were also specced at 88% efficient. 20 amp range would probably be plenty for one side at a time with enough of an undervolt.

Nice find on the PSU's, much preferable to an additional Buck Converter. As I am in the UK I will take a close look at the spec on the Sea Sonic one and may give one a try. Can't see where it says 10V, can you point me at that bit?

Rich

according to this pdf he is wrong


http://www.jameco.com/Jameco/Products/ProdDS/2188422.pdf



it lists the range for the:


 SSE-3201 PF-12  AS 10.8 TO 13.2     >>>   320.4 WATTS
 SSE-4501 PF-12  AS 10.8 TO 13.2     >>>   450.0 WATTS


TRY http://www.ebay.co.uk/itm/Sea-Sonic-Electronics-SEASONIC-SSE-3201PF-12-320W-Telekom-Full-R-SSE-3201PF-12-/400876113708?

Thought they both specced to go down to 10 or 10.2 volts, guess I misread it. I suspect they'll both get real close to 10V though, the "spec" adjustment range usually is noticeably narrower than the real range.

 Be nice if someone could find some similar PS with 90+ efficiency, though - as long as the price isn't a LOT higher.

 8-)


 I saw the SSE 4501, but Jameco wants somethign like twice as much for those. Almost certain you could get away with one of them per S5 even at MILD undervolt, but not as much margin and the price doesn't make it worth it unless you're VERY VERY space limited.

 I do like the 60mm fan on the Seasonics, should be quieter than the more common 40mm screechers....

10.8V - 13.2V is quite precise so would not expect to see anything better than that. It would be useful to be able to get down to 10.8V but if I am going to spend the money on a new supply I want to be able to get down to 9V to keep making money as long as possible, so will keep looking.

Rich

One of the other PS of the non-Seasonic maker on the Jameco page was also specced 10.8-13.something, but on IT'S data sheet it showed a "typical performance" page where the PS would actually adjust below 10V.

 The Seasonic unit might not "exceed" it's specs by that much though.



 On the other hand, it's a lot less of a risk taking one of these $60ish PS and digging into one to see if you can modify it minimally to extend the lower end of that adjustment range.

so im reading this thread and while i didnt read all the posts i did see someone getting mad about what seemed like money loss with equipment being purchased and not trusting what this guy says but why wouldnt he/she just buy a server psu that can have a voltage range from 9v-15.8v? thats what i did and i have been undervolting my s5's for months now....the only diff for me is the machine will not start hashing unless the voltage is 12v. once the frequency is set and the machine is booted i have to turn the pot added to my psu's to lower the voltage to match whatever frequency i choose. if i go too far the machine gets more hw errors if i hit the number needed everything is fine.

I assume you have one of the earlier Hash boards, would be good to know the version? Also would be great to know the make & model of the Server PSU that can be adjusted from 9V - 15.8V? I have three deiffernt Server PSU and none of them have I found a way of getting that sort of adjustment?

Thanks Rich

It's not so much that folks are mad, it's more that we want to be able to undervolt our existing S5 units *IF WE CAN* to extend how long we'll be able to mine profitably with them and give a better chance of a positive RoI on them (or give more OF a positive RoI on them if we do manage or already have managed to attain RoI on them).

Well look at it from my viewpoint.  My power cost is high.

what is the make and model of your server psu?

Am I missing something? Maybe you love to make things more difficult than they really are? If you are able to buy and install DC-DC converter, I am sure you can easily adjust your PLATINUM PSU to deliver 10V only. I did 10.6V without opening my Fortron Raider 700W 88% PSUs.

Most of PSU has "fine tune" voltage potentiometer, for exammple Fortron PSU has this accessible through fan grill. If you are not happy with voltage, you can go inside and by using "pencil trick" or changing resistor you can do more. Lowest voltage is limited by UVP which is different on each PSU, but you can easily overcome even this by cutting UVP line.

I also did the trick for server DPS-2000BB which works stable at 10.7V at PSU side, so S5 supply voltage can be around 10.3-10.5V which is good enough for 0.33J/GHs and very little effort.

I don't think any of us are trying to make things difficult, my favoured solution would be to adjust down one of my server supplies. However I have 3 different ones, none of which have any adjustment pots, and online I can find no mention of how to adjust them. It would be great if you could list the suppliies you have been able to adjust, how you did it and the voltage you were able to get down to? Ideally we need to get to 9V, however even 11v - 10V would be of use in the short term.

Rich

so this should have a pot to go to 10.8?

http://www.newegg.com/Product/Product.aspx?Item=N82E16817104181&cm_re=fortron_raider-_-17-104-181-_-Product

can't find a 700 watt

I have this one in my house:

http://www.newegg.com/Product/Product.aspx?Item=N82E16817104167&cm_re=fsp_group-_-17-104-167-_-Product

I could look for a pot to lower it a bit.

 Not from what I've seen of most recent designs. It's quite common of late to have no pot to adjust voltage at all.

I have found a 636 watt psu  88% efficient but costly at 128 usd.

I have 2 s-7's on order and I have one of these psu's on order


http://www.onlinecomponents.com/datasheet/hrp60012.aspx?p=37810156

model is Mean Well HRP-600-12 

adjusts 10.2 to 13.8  88% eff

I even found the absolutely best possible psu but it cost even more


http://www.onlinecomponents.com/mean-well-hlg600h12a.html?p=45585982


http://www.onlinecomponents.com/datasheet/hlg600h12a.aspx?p=45585982

HLG-600H-12A

note that A means it has a pot adjustment  10.2 to 12.6

this is 92% eff with no fan!  but it is 198 usd and is only 480watts

It does allow for a quieter miner but is too pricey.

With the cheap model HRP-600-12  I get up to 636 watts.

I will find a freq that allows me to run at 600 watts and 2400 gh.  say 150 vs 300

I will test it with the evga 1600 p2 making sure I am doing around 600 watts I will remove it

I will then use the meanwell  and once it fires up at freq 150 2400gh  600 watts 12 volts.

 I will back the pot down to 10.8  we should get a good watt drop off and the machine should run well.  maybe 500 watts for 2400 gh

I will then know if the s-7 has lower watt then rated.

Will be very interested in how you get on. I can run my S5 at the default 350MHz on 11V with no HW errors with a good saving. The HLG-600H series looks very nice, with high efficiency, no fan and a good range of adjustment, pity it's so expensive.

Rich

Per the specs on the S7, it might not be ABLE to undervolt - and almost definitely won't undervolt to the point a single 600ish Watt PS will run it.
UnderCLOCK might get there, can't hurt to try it.
 I don't see the point of that much underclock on it though, if you have to crank it down that far to be profitable, your electric rate is so high you really shouldn't waste power on mining.


 Unlike previous Bitmain miners, they are NOT running the S7 at the max voltage rating of the BM1385, they actually picked the MIDpoint of it's (so far) published voltage options.

you don't understand my goals.   

sound is my issue.  I have a 2.4 cent location  but I need quiet gear there.


which means fans need to be swapped.  power needs to be cut. I also need to find bottom voltage. For longer use.

The net is difficult to explain in detail as  people do not like to read long posts.

BTW if I am correct this machine can do 0.20 watts or maybe 0.18 watts  if so   then a 636 watt psu will allow  a down clock to 3000gh.

I will have a close to silent s-7 that is more efficient then any other piece of gear on the market.

At 2.4 cents and 0.18 watts  this gear will survive the ½ ing

perfect, so here is the "flip the penny twice" thread. Im getting @ 11.1V ~0.48 - 0.47J/Gh and I always tought it is a good result. So there is even more in it.
The only adjstable PSU (10.2-13.8V) with 88% efficiency I saw, was a Meanwell HRP-600 (http://www.meanwell.com/webapp/product/search.aspx?prod=hrp-600).

yes there is  now if you can find these  2 psu at a good price even better

Well, I dont think so (saw it for $240 and just thought "no way") so, 128USD is really good.

My 700W Server PSU (HP G5 412211-001) has a pot for voltage adjustment, but it adjusts between 12.6 - 12.004 V - it keeps the 12V under load. Even having a pot on a PSU doesnt imply the opportunity for a propper adjustment rate. So in my case it couldnt be worse.

Doing a general search on the net and ebay Meanwell have a very big range of PSU's. Quite a lot of them show adjustment from 10 or 10.2 Volts. They seem to have a good name in the PSU World and there are good data sheets on them, so definitely a cut above your average Chinese PSU manufacturer.

There are so many available that I need to spend a bit of time researching them carefully but will probably then buy one. The other "idea" I am considering is 2 x 5V PSU's in series if I can find a couple at a good price to play with. They typically have adjustment from 4.5V to 5.5V which then gives an almost ideal 9V to 11V range.

My only concern with all the Meanwell supplies is that the efficiency is typically under 85% to 88% so not up tere with a Platinum Server PSU with 95%. Need to do some maths to make sure you are not throwing away too much?


Rich

If you're losing 10% efficiency by getting those PSUs, why not use the PSUs you already have and use a good volt step down at 95-98% efficiency? Depending on what you have on hand it would be more efficient and more effective?

This is one of the several other options I am considering. Top of the list would be to be able to adjust down a Platinum 95% Server. Weather a lower efficiency adjustable PSU is better than a VRM on the output of a Platinum PSU needs some calcs & measurements to be made. I have ordered a couple of the VRM modules that Phil identified and we will see how those perform when they get here.

Rich

Nice modding around here guys  ;D
I just got me an adjustable PSU and let the games begin  :D

well one of the meanwells is 92%  the other is 88%

of course the 92% is the more expensive  choice  198 usd for 1 and 170 usd for 10

note the A at the end of the model is the pot  adjustment model

http://www.trcelectronics.com/View/Mean-Well/HLG-600H-12A.shtml

https://www.trcelectronics.com/ecomm/pdf/hlg600h.pdf



the cheaper one is 88%

 121 usd  for 1 108 usd  for 9

http://www.trcelectronics.com/View/Mean-Well/HRP-600-12.shtml

https://www.trcelectronics.com/ecomm/pdf/hrp600.pdf


The 92% is fanless and maxes at 480 watts 24/7/365   but I would think a fan lets it run with a bit more power.

I purchased the 88%.

  It arrives next weds  I am waiting on the s-7's

I will try to run 2 blades of the 3 under volts and under freq
I will try to run 3 blades of the 3 under volts and under freq.

If I lower the power to 600 watts and get .18 watts a gh

I am at 3333gh

The gear will be quiet.-------------really big for me

and at .18 per gh I am ahead of the field

If it does not work I only spent 128 with the shipping to find out.

I have used HP DPS-600 server powers on S5s upto 400mhz and they have been running 381mhz for months now.
0.001% error rate at 381mhz, powers are 47A but seems to work over specs and are dirty cheap from Ebay.
I have tested them with outboard trimpot and they can adjust to 10.5V. I haven't feed low voltage to the miners yet.
DPS-600 have a current share port so at least 2 can work parallel on S7 maybe.
 

Where did you connect the trimpot?

Hey Phil, is your location taking other peoples hardware also? I would be glad if my Hardware would be hosted in such a location, since here in EU i pay 20€ cents for the KW/h...

OK I had a couple of HP DPS-600 PSU's as I had bought them because they were reported as being adjustable. The ones I have are marked Series ESP135 Model PS-3601-1C but are reported on the Net as being the same. They have the same HP Spares number 338022-001.

I tried the voltage reduction pot when I first got them, 5K pot from (-12V to the Voltage input pin) but it resulted in almost no adjustment and then the PSU went bang... So I put it to one side and got on with other things.

So this Morning tried the second DPS-600 and it works fine. I can adjust from 12.3V down to 10.6V. I suspect it would go further with a greater -ve voltage? What went wrong with the first one we will never know?

So I will give the PSU a try on the S5 and see if it can deliver the current when the voltage is reduced? If it does the only snag I can see is that they are reported to be only 81% efficient and presumably that is at 12V, so may be worse at a lower voltage? This could throw away a lot of the gain, so will have to make some measurements.

Rich

From ultimaterc.com :

"Or use a single 2k-10k pot with the outer legs tied to pins 3 and 5 and the center wiper to pin 9 for voltage adjustment above and below 12v. "

I tested 10k trimpot which I used for S1 undervolting and got 10.5-13.8V until over and under protection kicked in.

DPS-600 goes little over specs with overclocked S5 but I have used them 24/7 since I got my first or second batch S5.

ESP135 has slow speed fan connected  at factory otherwise specs are same, fan is auto adjusted to temperature, but some modells start at full speed if You don't connect pin 4 to ground .

Yes I saw that you could connect the pot such that you can go over & under Voltage, but have no need to increase the voltage so just put it between 5 & 9. Do you find that when you turn the volts down, with no load on the PSU, the fan speed increases?

Rich

I only tested volt limits I didn't make any other testing.

Power usage from wall was 700W with 381Mhz S5.

It seem to me Bitmain are trying to make their miners NOT undervoltable, basically unhackable. S1 pen moddable, then S3 no longer, then S4's volt control get disable in later firmware, etc.

Maybe we can find a way to crack the S5, but if they do, they might "patch it" next time... maybe keep the good solutions under wrap?

I agree that Bitmain seems to be making it more difficult to undervolt than they could. It is unclear to me if this is driven by cost reduction and simplifying support, or if it is driven by a deliberate strategy to have miners become uneconomic sooner than they could?

However as a hack I think it was and will continue to be possible. S1 yes easy to undervolt with either the Pencil Mod or a resistor change. S3 no change only a simple resistor change needed. S4 designed with undervolting built into the firmware, but as you say later removed. Still unclear why this was done, however from a hack point of view you just use the old firmware.

So moving on we now have the miners with a string supply. Also let's remember that they initially told us with the S5 that with a 9V supply you would see 0.2J/TH. This was later removed however my current theory is that the initial design was flawed and when the voltage to the string was reduced the string stopped hashing. On the latest revision of the hash board V1.91 they have made a change to add an oscillator for every  4 chips in the chain, and this "seems" to allow undervolting.

If we now look at the S5+ and the S7, which I have only seen pictures of, there appear to be oscillators for every stage of the chain. So, yet to be proven? I think that they will both undervolt.

The efficiency gain you can get with undervolting is however reducing as they push the factory release of the product less hard. S1 could be doubled, S3 and S5 each less and the S7 has been released with the chip core voltage at the mid point, however still gains to be had.

So undervolting may not be as simple as the pencil mod and Bitmain may not be encouraging it. However I do not think they are deliberately making it difficult, they are just not spending any money on making it easy.  :)

Rich

 1) you're not losing that much efficiency. Many of the Meanwells I've seen could be rated as "gold" by ATX standards, even the lower ones are commonly 88%.
 
 2) Haven't found a stepdown YET that's specified to run LONG TERM at the power draw of an S5 per hash board, a couple talk about "higher possible with a bigger heat sink" but no actual spec for that.

 3) The PSUs I already have will probably be getting transitioned to running an S7 or three....



 Side effect of their "keep it cheap" string design, doesn't seem to be deliberate.
 The old "pencil mod" was about changing an on-board regulator that doesn't exist on their current designs - and was STILL far inferior to Spondoolies methodology.




 Wish I could find a place with affordable rent and enough power/cooling in Chelan or Douglass counties.
 Then again, if I had $50k+ to put into this I wouldn't have to worry about the rent as much.

 8-O

Seem pretty deliberate to me when the hardware design support voltage control but the option get locked in newer firmware, even though if you dig enough you can unlock it again.

 Just where in the hardware for the S5 is "voltage control" supported?

Voltage control is achieved by reducing the 12V supply voltage. As the chips are powered in a string, like Christmas Tree lights, this reduces the core voltage to each chip.

Rich

I found another mean well  this one is decent price and should be able to run the s-5 at freq 175

88% efficient  can go to 10 volts



 http://www.trcelectronics.com/View/Mean-Well/RSP-320-12.shtml


https://www.trcelectronics.com/ecomm/pdf/rsp320.pdf


https://i.imgur.com/SrMao0Q.png

Looks good Phil, Meanwell seem to have a very big range of PSU's. I picked up, at a price I could not resist last night, 4 x 5V Meanwell PSU's from ebay. Am going to try them in pairs as they should give adjustment from 8.6V to 11.6V.

 http://www.slotforum.com/forums/uploads/1440747800/gallery_2150_2322_193627.jpg (http://www.slotforum.com/forums/index.php?autocom=gallery&req=si&img=72010)


Rich

 I'm not sure but I think that's the same RSP-320-12 I mentioned as one of my original 2 links, just from Jameco instead of from TRC.
 (if it's not, then I have changed my mind since then on the "optimal" one as it's the one in my booklinks.)
 Mouser also carries them, I have noticed, but for a couple bucks more, and at least 1 seller on Amazon in the same price range.


 I dunno if they have enough isolation to use them in series, DO let us know how that works out.

all my testing will be on the s-7.

I have done a fan mod on the one I have at my house.  huge improvement in sound.

links to two of these psu's

https://i.imgur.com/5JvfR8m.jpg
https://i.imgur.com/kh94dIs.jpg
https://i.imgur.com/2vniinV.jpg
https://i.imgur.com/mMM3ydE.jpg
https://i.imgur.com/jjrUOa4.jpg
https://i.imgur.com/v058Wvk.jpg
https://i.imgur.com/Qc6o4pK.jpg
https://i.imgur.com/lLgxB28.jpg
https://i.imgur.com/vPGNi5W.jpg
https://i.imgur.com/sHBG6GR.jpg


I will post a few photos of the  fan mod I did


a 90 mm noctua fan
https://i.imgur.com/5JvfR8m.jpg

please cover the ac in or you can kill yourself

 https://i.imgur.com/kh94dIs.jpg

HP DPS-600 / Series ESP135 Model PS-3601-1C - (HP Spares number 338022-001) PSU Test

Ran some tests today on the DPS-600 PSU with a voltage adjust pot.(-12V to the Voltage input pin, Pins 5 to 9)  Bottom line not much use with an S5.

The pot allows adjustment from 12.2V to 10.5V. (If adding a pot put a 150 Ohm resistor in series so that that is as low as you can adjust. I think this is how I blew the first PSU?)

Measured the efficiency of the PSU and at 12V it was 82% Good news was that this only reduced to 81% when set to 10.5V

The Bad news is the the output power is significantly reduced when the voltage is reduced. The rated power from 12V is 560W, this reduces to 220W at 10.5V This is unfortunately not quite enough for an S5 with both hash boards connected. I did however test to see what the best with 2 hash boards that could be achieved.

This was at 11.6V and 350Mhz (Yes the S5 does not need 12V at the rated frequency) This consumed 559W at the wall for 1150GH giving 0.486J/GH (with 12V 0.51J/GH)

With a single hash board connected best was. 10.6V and 300MHz which consumed 211W at the wall for 495GH giving 0.426J/GH


So it's not a bad PSU with 80+ efficiency and can be voltage adjusted. However because the possible output power reduces with voltage it unfortunately does not have enough power below 11.6V for the S5.


Rich

Hmm need something better, this is nearly the same as just running the S5 on stock settings on a Platinum or such PSU. Thanks for testing that unit.
Maybe two units would work, one per PCB?

At 200w you'd need to go down to 9.5v~ iirc thats around where the power drain is under 200w and is about the same hashrate as a S3.

Wow, thanks for testing that. To have a 0.426J/Gh with an ~80% efficiency PSU is quite something. Also the temperature should drop @ 10.6V (less noise). I think its worth the effort. I will do some testing soon (no time for that at the moment, so in 2 weeks I guess).

Yes agreed I would need to get down to around 9.5V, trouble is it won't go that low & even if it did there would then be < 200W available as power will continue to fall. So an interesting experiment and good to get some real at the wall numbers with reduced voltage. All my earlier measurements were measured on the input to the miner, so taking no account of PSU efficiency.

I am now testing with two 5V PSU's in series, have adjustment from 9V to 12V. :) Good news is that they work, will be Tomorrow before I have some results. One feaature that holds things back is that on both my S5's one hash board better than the other, so you have to set the voltage for the worse one. At lower voltages seems to be about 0.3V difference for the same error rate. Have not attempted to understand why one is better than the other, but would only take one chip in the chain to upset things.


Rich

Have measured the efficiency of the MeanWell HRP-150-5 5V PSU's with 2 connected in Series. BTW there seem to be no problems connecting them in series although I am being careful to adjust them both to the same voltage. The DC output is isolated from the metal case.

Efficiency measured at 81% from 9V to 10V & 83% from 11V to 12V. So a bit lower than the quoted 87%, but I always seem to find that. Could be my measurement technique or perhaps the Manufacturers are a bit generous?

Here is the setup with the PSU's connected in series, with some cooling from the Miner exhaust, although they seem to run quite cool without a fan. Will measure the actual temperature they get to at some point. 5V PSU is rated at 70 Deg with a sensor on the Power Stage heatsink. Ambient needs to be below 45 deg for full rating.

http://www.slotforum.com/forums/uploads/1441555584/gallery_2150_2322_233493.jpg (http://www.slotforum.com/forums/index.php?autocom=gallery&req=si&img=72250)

Measurements of Hash & J/GH to follow.  :)

Rich

DPS-600 has a current share pin so You can connect them in parallel to S5.
10.5 V 40A should be enought for undervolted/clocked S5.
Small DPS fans stay quiet when power is low and You still have a under 40$ power source.
Maxed DPS fans have a very annoying high tone whine.

I have 3 S1 undervolted with DPS-600s as livingroom heaters 40db at 1m.

Like RichBC said (dejavu), at 10.5V it support 200W~, not the full rating from when it's ran at 12V. So you'd need two for a S5. For a S3 and a S1 its plenty.

"Ran some tests today on the DPS-600 PSU with a voltage adjust pot.(-12V to the Voltage input pin, Pins 5 to 9)  Bottom line not much use with an S5.  "

One is not enought but two is. Quick search from net gave me a price of over 50$ per Mean Well 5V supply and You need at least two of them. Efficience is about same and You can get pair of DPS-600s with wires at 40$.   
17$ per DPS-600 shipped; RC servo extensions for on-off pins, trimpots and current share; molex-PCI-E connectors for power feed. 

DPS-600 is easy to hack You don't need to open it.

This is very interesting folks. I wonder if perhaps this will become even more viable with used S5's that should come to market at reduced prices as the S7 roll-out happens. Something like this might well allow an S5 to be "tamed" enough in terms of heat and noise and also efficiency.

DPS-600 would be fine except that the power drops off with the voltage reduction and will not go low enough in voltage, so have ruled it out as an option for the S5. The Meanwell 5V PSU's I picked up 4 from ebay at only $45 the lot delivered.  :)

I have made some measurements with the Meanwell 5V PSU's in series, here are the results.



The efficiency should be better at 100 & 125Mhz but is being held back by the less good Hash board, that needs a higher voltage, particularily as you get near 9.5V. I will make some measurements on the single better hash board at some point. However not bad.  :)

Rich

Why don´t you take this one (http://www.meanwell.com/webapp/product/search.aspx?prod=HEP-150)
or this one (http://www.meanwell.com/webapp/product/search.aspx?prod=ELG-150)
or this one (http://www.meanwell.com/webapp/product/search.aspx?prod=hlg-150h)
or this one (http://www.meanwell.com/webapp/product/search.aspx?prod=HVG-150)

I think these are in your range, or i am mistaken something  ;D

Problem with those & most 12V PSU's is that the adjustment range is too small, they only go down to 10.8V. Having 2 x 5V supplies give me the adjustment range I need, also the ones I bought were very chap compared to the ones you have linked to.

Rich

Agreed, but you can rate the Output current to get to your desired wattage.
I did some test, i have to post the pictures, with an S1
If i lower the Voltage the current will go up to maintaine the power needed, so if you drop the current you will also lower the wattage.

If i pull 12V and 12A i get 144Watt
If i pull 10V and 14,4A i also get 144Watt -> that´s what my S1 did
So if i pull 10,8V and 13,3A i get 144Watt or lower...

If this is not feasible, forget what i just wrote.

Sorry I don't understand what you are suggesting here? The spec sheet for those PSU's says 10.8V to 13.5V. Wheras the 5V PSU's I am using have a spec of 4.3V to 5.8V, so 2 in series give 8.6V to 11.6V which is perfect for undervolting.

Rich

If i lower the voltage the current will go up to meet the consumption needed by the device.
So you can limit either the voltage or the current or both.

So i tested this on a S1 laying arround. If i give the S1 12V it draws 12,xxxA. If i limit the Voltage to 9,5V the current goes up to 15,5A to meet the draw of 144W by the device.
So if you limit the voltage to 10,8V the device is drawing 13,3A to meet the 144W needed, so you can adjust the draw by Volt, by Amps or both.
That´s why i opposed these PSU´s
If i am electrically completely wrong, please ignore my post  ;)

I still can't make any sense of what you are saying. The fundamental problem with the PSU's you have linked to is that the voltage will not adjust below 10.8V wheras I want to get down to 9V, simple as that...

Rich

Ok, i am fine with that  :D

OK good. :) You also need to remember that you are referring to an S1, which uses DC-DC Buck converters to reduce the 12V input to the Core voltage needed by the BM1380 chips. If you reduce the 12V supply going to the converters, as you say, they will just take more current to compensate. Not much point in doing this as they then tend to be less efficient and take more power.

The S5 is completely different and does not use Buck converters. The BM1384 chips are connected in a string (Like Xmas tree lights) and the voltage for the core of the chips is reduced to what is needed by the series connection. 12V / 15 devices = 0.8V. So now if you reduce the 12V supply the voltage to each chip also reduces. 9V / 15 = 0.6V. Combine that with a frequency reduction selected for an acceptable HW error rate and you get the table of Hash & efficiencies I have shown.



Rich

Ok, got it  ;D
I found one (http://www.henri.de/stromversorgung/schaltnetzteile/schaltnetzteile-9v/22252/6v-9v-netzteil-200w-26a-case-6v-7v-7-5v-8v-9v.html) with 89% and an adjustable VoltPoti  ;D

Yes quite a nice supply except that it only goes from 6V to 9V which is not a lot of use.

A word of warning for anyone who has not read some of the earlier posts in the thread. People had tried undervolting the S5 from early on but had little success as it stopped hashing if you reduced the voltage much below 11V. The two S5 that I have are both V1.91 Hash Boards which have 4 oscillators spread round the board as opposed to one on all the earlier revisions.

It is highly possible but not proven that it is these additional oscillators on the V1.91 Hash board that enable undervolting.

Rich

I´ll talk to that guy if the Voltage goes up to 9,4 or 9,5. As i understood you were searching for a high efficient 9V power supply. I´ll let you know what the tolerances of these PSU´s are  :D

EDIT: Talked to the guy. He said, "usually" these PSU have a slight range over the stated one. It could be that this one goes up to 9,4 but that would be critical to find out.

You are making this hard work, this is what I said earlier.


It's the ability to adjust the voltage in this range dependant on Difficulty & Electricity Price that is important. At any point in time the optimum setting for Voltage & Frequency changes and will change substantially when we have the halving next year.

Rich

I know what you said, i just was looking for one PSU in this range but i think your solution is the one to go  ;D

I am curious as to what happen to the miner when ran at over 350 to 400mhz undervolted. It seem like the test results so far were only extended to up to stock and then downward. I'M guessing the lower voltage you go to, the upper(stable) clock limit goes down?

It's very straightforward. The higher the Frequency the Higher the voltage needed to not get excessive HW errors. The Bitmain design point is for 12V and 350MHZ and they have been slightly conservative with the voltage such that even a worse case miner will have a low HW error rate.

Because of that most S5 running at 12V can be overclocked to 400MHz with an acceptable HW error rate. Conversely you can undervolt (11V) most S5 running at 350MHz and still get an acceptable HW error rate along with a J/GH efficiency improvement.

Rich

Thought so, thanks. I'd be more looking in the vicinity of something like 11.6V for 375Mhz. And eventually downclock/downvolt them to a usage of 450w for 1~THs. That would allow me to power 3 Antminer S5 from 1 120v 15a breaker :P

I got an S5 motherboard V1.3 and assembled a parallel DPS-600 power for it.
S5 didn't hash at 10,5V and I adjusted to 11V, I have now tested upto 300Mhz and got about 1000Gh/s with 0,004 error rate.
Family is sleeping more testing at daytime, fan speed was 2700 and 445W from wall with very small router at same plug.

With one DPS-600, 300 Mhz and unadjusted power with 12,4V idle voltage this same S5 took 550W from wall.

When the V1.9 S5s are made/sold?

@SLEI that result is what I have seen from the early testing that has been done on the S5 with not much less than 11V being possible, however still a nice gain. Would be interesting to see if you can push the frequency a bit more at 11V?

I do not know when the V1.91 was sold. All I do know is that it's the latest board I have seen and the date on the PCB is 28-March-2015 so some time after that?

I have listed all the boards I can find along with a few notes in this post in the thread.

https://bitcointalk.org/index.php?topic=1151460.msg12164839#msg12164839

As I have said in that post my best theory on why the V1.91 will undervolt is the multiple oscillators, however that is still unproven , but is the only significant difference. Oscillators could probably be retrofitted to earlier boards but would be a tricky job.


Rich

 Better efficiency on the Meanwells, if you grab the right ones.
 Cost vs. efficiency is usually a tradeoff in any power supply situation.



 S1 has onboard voltage regulation, no need to use an external "undervolt capable" power supply, and defeats the purpose anyway.
 S5 is a string design with NO onboard voltage regulation, you HAVE to undervolt them externally.


 While the 12V Meanwells usually spec to go down to 10.8, they'll usually go a LITTLE lower - not to 9V though.

S5 V 1.3 seems to be very moody, no start when cold at morning 300Mhz , volts were 10,9.

11,3V were enought for std 350Mhz hashspeed 1100 530W, fan 3700 and loud as std.

Now early at evening 10,7V is enought for 293,75 Mhz 930Gh/s and 415W 2400rpm fan.

I guess if you are near the limit of something just working or not, then you only need to change another variable like temperature a little and that's enough to throw it either way. Another factor is that the voltage needed to start hashing is slightly higher than the voltage needed to keep hashing. Anytime you have a system that is hashing if you have adjusted the voltage down since it started you need to reboot to check if it will actually start at that voltage.

I have been making measurements on individual S5 Hash boards and there is some variance between them, will post up the results when I have finished.

Rich

the 5 volt meanwells are a bad choice.  all of them  are not efficient.


 this one is good  my goal is 2 of these at 10.2 volts or 10.5 volts  running an s-7

if I can drop from 12 to 10.2  that is 15%      since no plat psu does better the 94%  this one is 88%

   so I am better then 11% power improvement. over a high end plat

http://www.trcelectronics.com/View/Mean-Well/HRP-600-12.shtml

https://www.trcelectronics.com/ecomm/pdf/hrp600.pdf

https://i.imgur.com/QOqF6dD.png
https://i.imgur.com/imWzE2o.png

Agreed the efficiency is lower at the lower voltages, the ones I have (HRP-150-5) are rated at 87%, although I measure them a bit less than their rated efficiency as I do all the PSU's I have.

They are however the only off the shelf way I have found to get a voltage range of 9V to 11.5V which covers the full undervolt range. Also I was very lucky with an ebay purchase and bought 4 for $45 delivered which was a bargain I could not pass up.  :)


Rich

on a completely different take for sound control….  which goes hand in hand with under clock..  I found this


http://www.ebay.com/itm/8-Inch-Hydroponics-Duct-Muffler-Inline-Fan-Blower-Filter-Silencer-Noise-Reducer-/261492562812?

this is too much money as the s-5 needs one

and the s-7 need two  



but this http://www.ebay.com/itm/220659184713?

inside this

http://www.ebay.com/itm/Sonoco-Sonotube-cardboard-warehouse-storage-tubes-concrete-forms-/321172021836?

or inside this

http://www.ebay.com/itm/692201-8x4-Concrete-Form-Tube/391158475313?


should kill off a lot of noise.

I am thinking the s-7 will need two  2ft long 8 inch tubes

The s-5 will need one 2ft long  8 inch tubes.

I can get tubes at home depot for 6 bucks  each tubs makes 2 mufflers.  I ordered enough foam to build. 18 feet of mufflers or about nine 2 footers.

I am pretty excited as I think I can get s-7's to run quiet and at 4000gh at 900 watts.

This means I can do 5 in house.  1 at my friends office and 1 at my other friends wood working shop.

that would be 7 x 4th = 28th

yeah then do .87 x .87 = 0.7559

and it    kills the efficiency    you said you were at .8 or .81   I am pretty sure this is why.

Why have I got to do .87 x .87 ?

you combined the 2

5's into a 9-11 volt.  I think it  multiplies the efficiency   which lowers you closer to .80 not .87


Not sure .

Is there a hacked firmware for S5 which allowes fan to turn slower than 2040 rpm?

I threw underwolted underclocked S5 to porch for tomato heating and reported miner temp is 32/27 C and fan speed is 2040, same as non hashing miner had at 50W power draw.

When you set fan to 20%, it doesn't go any lower?

2040 fan speed is usually the lowest I see even when the miner is very undervolted & underclocked. I have seen 1920 but only when the miner is very cool.

Setting to 20% does not set it any lower, but have not fully understood the % fan speed algorithm, however the miner does run progressively hotter as you reduce below 50%.

Rich

 Nope. each supply does half the power, so you take the efficiency of each supply and average them for the overall efficiency.

 You would only MULTIPLY efficiency if you were feeding the output of one supply into the next supply, like feeding one of the "buck converters" from early in the thread from an ATX or server PS.

I see, the minimum and maximum must be coded-in. It is probably something akin to 35-80% or something. For instance setting it to 100% does not raise it over 3840 iirc. And 3840 is about 80%~.

Beside doing some digging in the firmware to lower it further, your other option would be a better noise/cooling ratio fan. Or lower the voltage to the fan.

OK let's put aside for the moment PSU efficiency and have a look at some hard data on the 4 individual S5 Hash boards that I have now characterised.

First the measurement Technique.

For all tests I have used the Pair of Meanwell HRP-150-5 5V PSU's shown in the earlier picture. These are connected in series and the Power at the Wall measured on the Meter also in the picture.

I measured each Hash Board in turn with the second card disconnected, so the measurements will slightly undercall what is possible with 2 Cards as the Controller Board & Fan are just being used for a single board.

I adjusted the voltage at each test point to give about 0.01% to 0.02% HW error rate. I found it much easier to go for this in time terms rather than trying to adjust for 0%. In practice you might want to up the voltage a notch and have a lower HW error rate?

So there are 4 tables below showing for each board a range of Frequencies, Supply Voltage, Core Voltage, Power at the Wall, Hash Rate & J/GH.


There is some variance  between the boards, which in practice in a 2 Board S5 means you would have to adjust the voltage for the worst board of the pair. Ideally you need a matched pair in a miner so looking at the results I will probably pair up S5n1 Side 1 with S5n2 Side 2 & S5n2 Side 2 with S5n2 Side 1.

So useful J/GH gains at all frequencies by optimising the voltage. Best J/GH being 0.343 on S5n2 Side 2 at 175Mhz with a supply voltage of 9.2V & a Core Voltage of 0.61V

At some point it would be good to try and understand the Board variance. However I think this will be difficult with the string design as it make isolating chips very difficult.

Rich

Is it possible to upgrade V1.3 board to v1.9, are the board different or only parts missing from older boards?
Any detailed photos?

I had older firmware and fan procent thing wasn't there, I upgraded but I don't have any clue what this setting does?

"Customize the fan speed percentage" percentage is counted from what?
If miner is very cold I have the same 2040 speed still.
  

Undervolted S5 don't like to bee treated  as farming tool (heating tomatoes) and rebels all the time.
I had to adjust volts to 11 and Mhz 306, 3G mobile network for this miner don't make things easier either.

Look back at this post and you can see the different versions of the Hash board.

https://bitcointalk.org/index.php?topic=1151460.msg12164839#msg12164839

It would be possible to upgrade the V1.9 to V1.91 as it has the pads for the additional components, however a tricky job unless you are equipped to solder surface mount components.

Upgrading the earlier versions would involve making a small daughter board with the additional oscillators and then patching them into the circuit. Again a tricky job.

Also remember it is only a theory at the moment that it was the addition of the oscillators that enables the boards to Hash at a lower voltage.

Rich

Might have just set a new S5 Record?

I cannot get Hashing to start reliably with less than 9.3V Supply, 0.62V Core. However once hashing you can wind the Voltage down.
So at 100MHz which is 330GH I got the Supply down to 8.4V, 0.56V Core. Watts at the wall were 97W which gives a J/GH of 0.294  :)
No use in practice as it only ran for 10 Minutes before one board stopped hashing, but first time under 100W & 0.3J/GH

Rich
 

Anything around 0.3 is pretty fantastic regardless. Did you try under 100mhz just for fun?

I think the limit might now be being set by parameters other than frequency? I think I may have hit bottom limit on either the Core Voltage or the voltage for the IO or PLL? However it would be interesting to try lower if someone can tell me the file that I need to SSH into to add an additional frequency?

In addition to this I have identified another difference in the V1.91 PCB which may play a part in the board being able to undervolt? Not quantified yet but they seem to have done away with the LDO regulators for the chips? Although this could be a benefit at "normal" voltages it could also be a problem when they are significantly lowered? More measurements needed will report back when I have more data.


Rich

I was just thinking, maybe at 86.5 or 75mhz the board would take maybe lower volt OR you can up the volt just a tiny bit but still get better efficiency at lower hz / hashrate.

Agreed, however 100MHz is the lowest that is selectable from cgminer. So I need to know the file to edit to add an additional frequency like you used to have to with an S3?

Rich

Indeed, you would need to go to config/cgminer.conf and edit the json manually. For instance mine is set to " "bitmain-freq" : "3:393.75:1f06"," or " "bitmain-freq" : "3:381.25:1e06",".

I am not sure exactly what the hex value means, 1e06 is 7686 and 1f06 is 7942. What could it be? Voltage? Would be funny if thats how voltage is controlled on S5 but i doubt it would be this easy.

There must be a table somewhere in amongst the files with all of all the frequencies you can select from 100MHz to 500MHz? Not at all up on the firmware side of things so need to know where to look. I would hope that you can then add say 75MHz to the table and then select it from cgminer? I suspect there will be a reg value for the divider frequency that can be worked out and also a delay variable? Just need to know where the table is?

Not expecting to find any voltage control, just frequency?


Rich

The only list i have would not be of use to us;
http://pastebin.com/bPpbWbEb

But if later tonight no one gave us the answer, i will try to just figure it out. It can't be that complicated.

Yes that table looks correct for the frequencies, same values as in the BM1384 Data Sheet. 75Mhz is probably going to be 0583 and will need a delay something like 52ms. Just need to know where the table is?

Rich

I'm not sure how to set the delay or where it comes into play. I'm glad you figured it out because i thought 75 was 4B in hex. So clearly i am missing something.
What do you mean "where the table is"? Do you mean where to plug the value? If so then that is strait in the config json in /config.

As I said the the software is not at all my thing, but I assume there is a file that you can SSH into and edit on the controller board that will have the frequency divider & delay values? Same as there is for the S3?

Rich

Yes. I use WinSCP myself, pretty nice as you can edit everything from your windows computer more normally. Anyhow the json config file is /config/cgminer.conf. Open it and you will see the normal JSON style config.

Relevant line is;
"bitmain-freq" : ""

Example of proper value "bitmain-freq" : "3:393.75:1f06".

So let's take stock on where we are on the project? Underclocking and Undervolting has proved possible on two S5 Miners with V1.91 Hash boards. There are differences in performance between the 4 boards tested which needs to be understood at some point.

Improvement in J/GH is possible at all Frequencies when you have the ability to adjust the voltage. This includes the Standard Frequency of 350Mhz where the voltage can be reduced from 12V to 11.1V reducing the Watts at the Wall from 568W to 510W and improving the efficiency from 0.492 J/GH to 0.442J/GH

Best efficiency with reliable starting and operation was at 150MHz,  9.4V supply (Core Voltage 0.63V) consuming 166W at the Wall giving 495GH with an efficiency of 0.335J/GH.

Best efficiency seen by winding down the voltage after hashing had started, but not sustainable was at 100MHz, 8.4V supply (Core Voltage 0.56V) consuming 97W at the wall giving 330GH with an efficiency of 0.294J/GH.

I feel that I have not yet found the best solution to an efficient, cost effective variable voltage PSU. Best that I have is 2 x 5V Meanwell PSU's in series. These give the full adjustment range needed for undervolting, but are a little low on efficiency at 82% and also a little low on power as they can only be used up to 300Mhz.

The DPS 600 Server PSU allowed adjustment of the output voltage from 10.6V to 12.25V but was disappointing, as when the voltage was reduced so did the power available.

I have also tested the DC-DC Buck Converter that Phil identified, on the output of a 12V Server PSU. The efficiency was extremely good at 96% however they were only good for 10 Amps as after that the load regulation was poor. However the voltage adjustment range was good and they are an option for lower power on a single S5 Hash board. (More detail available if people are interested?

So what next? I think the fun is now over and I need to knuckle down and work out why the V1.91 can be undervolted and the earlier versions can not? Once that is understood I want to explore if it's possible to improve on the results I have and if there is a way of enabling the earlier versions of the Hash board to be undervolted.

When I have worked up the detail I will describe the differences that I have found  between the V1.91 Hash Board & the earlier versions and will welcome any inputs as to the role that these play in enabling undervolting as a prelude to the next stage of the project.

Watch this space...  :)

Rich

Hmm indeed, personally i would like to find high quality PSU with easy variable volt control. I would sure love to see EVGA G2+(or such quality) with a led display and a turn knob that let you downvolt. If not then a higher powered PSU that runs 10-11.9v since those are the range i am interested in.

I would love to see how high you can overclock the unit while keeping the stock 590w~ consumption. And then find the most efficient speed that consume 450w~ per S5.
Personally i would want to run 3 S5 per 15a 120v breaker and this project can make it happen, tho obtaining specifically 1.91v's may prove challenging.

Meanwhile i hope you get to understand the 1.91v better, maybe it could lead to better volt control, then again maybe not, circuitry is above my paygrade.

My guess for 590W would be to get close to 400MHz with 11.5V giving 1320GH? At 450W the closest measurement I have is at 300MHz with 10.6V Supply (Core Voltage 0.741V) 400W at the wall giving a Hash of 990GH and 0.404J/GH. I could not push it any higher as I felt I was at the limit of the Meanwell 5V PSU/s, but I am sure that 1TH would be possible with 450W.  :)

Rich

At 400Mhz i have hit diminishing returns. Oddly enough the HWE% does not raise by much, only by <0.001%, however i only get a 5gh increase up from 393.75mhz which is 34GH/s up from 387.5hz.

I tried pushing it even further up. At 425hz i had 1.355Th/s for 692Watts and at 437.5 the hashrate dropped to 1.2TH/s, consumption 714watt and HWE% 0.3%. So i am not sure what is causing the hashrate drop. But it is not proprotionate to the HWE%.

Since then i found a trick to keep both board at about the same temperature, i just use a piece of paper to direct air from from a box fan vertically through the "fins" in front.

I may try again during winter with low temps. But i don't think that is the issue since 60c does not seem that higher to me and the temp was not any higher than the few previous clocks.

I wonder if in your research on the 1.91v you will be able to understand why the S5 behave this way at higher clocks?

I have not documented them very well but have seen examples of when the Hash Rate has not met expectations despite the HW error rate being relatively low. These have however usually been when I am quite undervolted relative to the voltage needed for a "normal" error rate. I usually aim for 0.002% or lower. However I have done very little testing at the higher frequencies as that has not been my main objective.

Hopefully the more work I do the better my overall understanding and that additional useful info and ideas will be found  :)

Bad news for me, with my 15c electricity cost, is that even with my most ambitious undervolt results they will only see me through making money until the Halving. This assumes that the 4% increase in difficulty continues. After that my only hope is that the S7 has become cheaper or that some emerge onto the 2nd hand market.

Rich

VirosaGITS thanks for you continued interest I wonder however if anyone else has any interest in my ramblings now that the S7 is released?

Anyway to continue  :) I am still working on the assumption that S5 Miners prior to the V1.19 Hash Board cannot be undervolted? This is in no way confirmed but is backed up by several members posting over the Months since release that they have tried and failed. I am assuming that their tests predated V1.91, here are a couple of examples :-



The V1.91 Hash board has two significant changes and I am assuming that one or both of them are responsible for enabling hashing at the lower Core voltage in the BM1384 spec sheet? I will describe these changes in my next post but it is interesting first to speculate what happened at Bitmain?

When first released the publicity included this statement.

When better power efficiency is needed in the future due to higher network difficulties, you may want to buy some special PSUs 9V DC with more than 10A output, which will allow you to have a 0.2J/GH mining efficiency, but at lower hashing speed.

Clearly they expected the unit to operate with a 9V supply, which equates to a Core Voltage of 0.6V. The 0.2J/GH was however slightly ambitious relative to the chip spec which is 0.249J/GH.  :)

This statement disappeared at some point with as far as I know no explanation as to why? Simple best guess would be that they found that with the release version the Miner did not hash at much below 11V. You could also speculate that someone in Marketing got a bit carried away with some engineering data and then it dawned on them that anything that prolongs the life of a miner is not good for future sales?

The more interesting point to me is what motivated them quite late on in the S5 life to make some changes that enable the unit to be undervolted, particularly as they chose to make no mention of the value of the change?

My theory is that Bitmain likes to experiment with ideas in a shipping product that will then be used in a new product. Examples of this are the S3++ which trialled String Supply later then seen in the S5 and the changes to the S5 board layout that then enabled board side mini heatsinks to be fitted, then seen in the S5+.

I will explain the 2 changes in my next post and then speculate further.  :)

Rich

Cheers, no problem, its a good thing to to put interest in and just as people are interested in undervolting S3's at the moment, S5 are coming up next.

I'm not particularly in a rush to underclock the S5 because it is still an efficient unit and i think i pay like 1/4 of what you pay for your electricity iirc you said you pay 0.15? But it still has a parallel effect to what i wish to do.

Of course the best would be to underclock it without using specials PSU but beside finding a bulk step down that has a high efficiency and current capacity, it ain,t happening. Maybe Jabberwock or Sidehack could make some PCI-E step down, i'm not sure if adjustable volt control could be a thing, but it might resolve our issue completely as for obtaining the required hardware.

For the S5 having low voltage support removed, i think Bitmain just cheaped out and rushed out production and sold the S5 for cheap to kill the competition. That would be my market movement speculation.

Three more 4% difficulty changes will see my most undervolted S3 with 0.64V & 125MHz giving 0.49J/GH at break even so I will be putting them on ebay as soon as I get round to it.  :)


So moving to the changes to the V1.91 hash boards. A bit complex so needs a careful read.  :)

1) The PCB was changed at V1.9 to make provision for multiple Xtal Oscillators, these were then fitted at the V1.91 rev. In all the earlier boards there was a single Xtal on the bottom chip in the chain  and then the clock signal was then chained through the 30 chips.

V1.91 has 4 Xtals, the original one on the bottom chip in the chain and then an additional Xtal after every 4 chip pairs.

As this is a cost addition I am sure that Bitmain must have had a good reason to fit the additional Xtals. Why this might improve operation when the miner is undervolted I do not know? However it is a contender for the improved performance.


2) Second change is a strange one. In the original design each chip pair in the chain had an LDO Voltage Regulator that supplies the PLL and IO circuitry.

The LDO was fed from the Core voltage of the chips 3 steps up the chain. This means with a 12V supply that the voltage into the LDO is 3 x 0.8V = 2.4V. Output voltage from the LDO is 1.8V for the IO & Analog PLL with then a potential divider to give 0.9V for the digital PLL.

The LDO for the last 3 chips in the chain are supplied from a small 14V Buck Converter, this voltage, when the supply is at 12V, equates to 2V  into the LDO for the last chips, 2.8V for one back & 3.6V for two back.

When the Miner is undervolted the input voltage to the LDO will reduce and with a supply of 9V the voltage into the LDO is 3 x 0.6V = 1.8V. This could be part of our problem when undervolting as the dropout voltage of the LDO is 0.3V. So this would mean that any voltage less than 2.1V would be at risk of being insufficient for the circuitry? 2.1V would be reached when the supply is reduced from 12V to 10.5V.


The change in V1.91 is to do away with the LDO's. The supply voltage for the analog  PLL and IO circuitry is now taken directly from Core Voltage of the stage above. The same potential divider is retained to feed the digital PLL The last stage in the chain retains an LDO driven from the 14V Buck converter.

So now looking at some numbers associated with the new means of supplying the PLL & IO circuitry is where things get confusing in relation to their value as an undervolt enabler.

So at 12V the voltage will be Core Voltage x2 = 1.6V. This is already very close to the data sheet minimum of 1.62V but almost certainly ok. However when we are undervolted to  9V Core Voltage x2 is only 1.2V which is well below the data sheet minimum.

It is just possible that as the core voltage is reduced the chip "likes" a matched reduction in the supply voltage for the IO & PLL circuitry, or it could just be a Bitmain cost reduction?

So at this stage all I can say is that this is a significant change with a significant effect on voltages when the miner is undervolted, so again may be the key to why undervolting is possible?

What would be good to know is what have Bitmain done on these two design points in the S5+ & S7 ? Comments welcomed on any of the above?

Rich

I can't really comment on the technical stuff.

Conceptually i'd ask, is it possible to change some regulator, resistors and shit to raise the volt of the thingabob that need a certain minimum while undervolting the overall board?

For the S3, check how much you'd get from Ebay and see what it'd cost to mail it to Canada (Probably prohibitive) but if the end price is comparable to stuff here i could be interested. If not i'm sure someone in the US would be.

I suspect that shipping to Canada would be prohibitively expensive but will look into it. Fortunately there still seem to be plenty of people around who have not done the maths on what is and will be profitable.  :)

Once I can get to the bottom of why the V1.91 board can be undervolted then there may be a way of making changes to the earlier boards. However at the moment I am just exploring the differences in the hope of finding out the reasons for the changes and to further my understanding of how the board has been designed and the key parameters that enable operation at different Frequencies and Voltages.

Rich

I tested one of the 15A DC-DC Buck converters, identified by Phil,  that are widely available on the net & ebay from $8.

http://www.slotforum.com/forums/uploads/1442596726/gallery_2150_2322_46222.jpg (http://www.slotforum.com/forums/index.php?autocom=gallery&req=si&img=73050)

Don't you just love the Insurance Tube.  ;)

Here is the test setup using an Electronic Load.

http://www.slotforum.com/forums/uploads/1441555584/gallery_2150_2322_88810.jpg (http://www.slotforum.com/forums/index.php?autocom=gallery&req=si&img=72490)

Here the results with 12V Input 10A Output at some typical Undervolt levels.


As you can see efficiency is very good with just a slight drop as you reduce the output voltage. My only criticism, relative to the listed spec, is that Load Regulation at much over 10 Amps rapidly degrades.


You will need one for each Hash Board in an S5 and the only real problem is that even then they do not have enough power to support frequencies above 225MHz.

In conclusion. Good price, good efficiency, ok for lower frequencies needing 10V supply or less. Above 11 Amps the load regulation is poor but if you are careful this "feature" can be used to provide a higher voltage for start up than running allowing you to undervolt further.  :)

Rich

Am away from home but took a controller board with me and have just got round to SSH into it. Have found the line you refer to above and as far as i can see the first character "3" is the delay with "3" being around 10mS, this number increases as you drop the frequency and is 10 when you get to 100MHz. Second number "393.75" is the frequency however I think it might just be the text that appears in cgminer? The third Hex number "1f06" is to set up the divider and corresponds to the data in the BM1384 data sheet.

So I think this is where the current selected Frequency and associated setup information for Delay and Divider ratio are stored? So yes editing them will probably allow a different frequency to be set.

However there must also be a file somewhere which has the complete table of frequencies and with access to that an additional Frequency, Delay and Divider Ratio could be inserted which would then allow selection from within cgminer?

Question is does anyone know where this table is?  :)

Rich

I think not, you would have to use the table we already have and do try to manually figure out which delay to set with the hex.  It is indeed possible that the middle value is literally "just for show".

Since the cgminer use the typical json.config format, there's no need to have a list of code line that you ssh vi edit-freq etc and just #'out the unused line.

I understand what you mean there should be some dictionary for the firmware to automatically change it but i never found it and it might be compiled in the image in boot at start, as such you could try to open image such as cd/mnt/mm1 initramfs.bin.SD for the S4, but for the S5 seem even more elusive. I don't know where it is.

Perhaps someone could elucidate the mystery or give a hint but checking file by file is tedious and i did not manage to find anything relevant. =/

Also for the step down, is it possible to put 2 in parallel or something to allow something like 200w~ per blade? May sound expensive but meh, i'd like something around 11v and i guess if they were adjustable as well it would be a plus, but i don't know how step downs/buck converters work.

Here are my results with the buck converters:

@175 MHz 10.06 Volts and 580 Gh/s ~215 Watts @ Wall -> 0.371 J/Ghs

So thats 27% less energy.

Despite I've had no HW errors @175MHz there were some @150MHz (100 per hour and less than 0.004%)

https://i.imgur.com/2KEcLr1t.jpg
https://i.imgur.com/mWotr0yl.jpg
https://i.imgur.com/iKsbW5Jt.jpg
https://i.imgur.com/3s4dZ9jm.jpg
https://i.imgur.com/m1RxBZwh.jpg


So thanks for the ideas to RichBC and all the other great guys.

I tried editing the line cgminer.conf and if you make any change even a single character then the frequency shown in the drop down menu in Miner Configuration is blank. I only have the control board with me so cannot see if the Miner hashes. Have had a bit of a search for a file with all the values in but no luck so suspect you are right that it is compiled.

Not sure about parallel connecting the converters would be concerned if they would power share?

flikflak nice results, which Buck converters are you using? Have you got a V1.91 hash Board?

Rich

I'm using two of those (http://www.aliexpress.com/item/250W-12A-High-Voltage-Input-Buck-Converter-Step-Down-Module-10V-60V-to-1V-48V/1708407463.html?spm=2114.01020208.3.10.b1IhgV&ws_ab_test=201556_7,201527_2_71_72_73_74_75,201409_2) little fellas.

There are some 40A/400-500W buck converters in the shop -> that should be enough for VirosaGITS. I wouldnt connect 2 in parallel to one board, because that would be like 2 different PSUs to one hashingboard.

And yes, its a V1.91. I will do some more tests later.

I have little electrical knowledge, so i do not know how to pair up buck converters together to raise the watt limit and keep the efficiency up to 98%. Basically it would be a god send, even if the end cost is 40$ per to keep it running at full speed but with much better efficiency. At least for some users and maybe me if i can get a bunch of the step down for cheap.

Maybe someone with more knowledge could answer as to whether you can pair up a buck converter to raise the watt limit/keep efficiency up?

Also maybe someone can tell us where the S5 hide the image, or the freq list.

New to this thread and TL:DR on the rest of it. GITS referred me here and told me to bring some data since I just picked up an S5 and am doing a project for the school with probably two of these things.
All power measurements are made using a Kill-A-Watt meter behind an HP DPS-800GBA power supply, for some odd reason putting out a loaded 12.65V (12.7V unloaded). Hash measurements are from the management screen on the unit's web interface "GH/S(avg)" box after roughly 10 minutes. Temperatures are in a room where ambient temp was high, around 28C, using the stock (incredibly noisy) fan.

Balls, won't let me actually embed the damn thing...
http://1slickvdc.com/other/mining/s5_chart1.png

Ouch that is bad efficiency. But most of that is because of the PSU itself so it's hard to say how much of it is due to the voltage. Its interesting still. What PCB version do you have? Its written in top right of the PCB under the bitmain logo.

Anyways basically the interesting point is 400-425, youre able to clock it just a bit higher and stay stable with your over voltage. But you get very bad efficient across the board. The highest i could get was 1315, and then it crash rapidly, while you crash a bit later at high volt. I guess it make sense.

Ultimately you normally would draw 580w at 350 and you're at 700, ouch. Also your efficiency go up and down mine didn't it was a bit better in the account of the the fan draw being the same and actual efficiency being the same.

That's why I really want to get the voltage down on that damn supply. The 600W version of that supply has a trim pot and people have dropped it to about 11.6V. My controller board says V1.3 (assuming that's the string that reads something S5 blah FPGA something. The only version number I could find anywhere. On the control board next to where the one hash board connector and the control board power connectors are. The PSU also reads about 35W unloaded.

Can the voltage be modified like my U3's, through editing the config? Saw this in the "monitor" section.

/usr/bin/cgminer --bitmain-dev /dev/bitmain-asic --bitmain-options 115200:32:8:7:200:0782:0725 --bitmain-checkn2diff --bitmain-hwerror --version-file /usr/bin/compile_time --queue 8192 --api-listen --default-config /config/cgminer.conf

one of those "--bitmain-options" params has to be voltage, probably 0782 or 0725.

You can set the option but the hardware doesn't use it. Since it has some string design or some such it doesn't have voltage control.

You can see the board version here on the PCB not the controller;
http://i1079.photobucket.com/albums/w501/bond007taz/20150129_071133_zpsce3ee8cd.jpg

S5_SPOWER_HashBoard_V1.3 is what it read but its quite possible you have a very early batch S5.

Hash board V1.3 also.

From a low-level sense, there's no reason the chip voltage absolutely couldn't be controlled from the software except by intentional design. Most likely to prevent twits from cranking it up and blowing out their miners. What about a hardware modification? It's a switching supply of sorts to step it down to chip voltage, there's got to be a voltage reference point somewhere that can be modified, eh?

I really don't know the details. Apparently its because they switched to a "string design", the voltage must be controlled at the feed/PSU level. But again only the 1.91v seem to support it without dropping chips.

Maybe RichBC can elaborate on that, but i'm not the guy for that.

Wait. "string" as in they put the chips in series on the rail?

some not so good news on s-7 underclocking.  using  this psu




https://www.trcelectronics.com/ecomm/pdf/hrp600.pdf


okay I set freq to 300 which is half speed  and I did  2400gh at 612 watts  which is normal  volts were at 12.15

I dropped volts to 11.85   2400 gh held   watts went just under 600 to 594


I dropped volts to 11.50 2400gh held watts went down to  579


At 11.25 volts   asics dropped off


so there is some type of governor/regulator  on the early  s-7   just like the early s-5.

and to be sure the controller was out of the power line it was run with a different psu steady at 12.15

Excerpt from the S5 manual:
"Notes: Input voltage should not be less than 12.00V, since it is based on serial power solution and there is no DC/DC inside the miner. Higher input voltage will cause higher mining efficiency."


What the balls? The only possible thought on why they would do that is an attempt to keep heat down. Other than that it sounds like a terrible idea in terms of reliability.

And they also had:

"When better power efficiency is needed in the future due to higher network difficulties, you may want to buy some special PSUs 9V DC with more than 10A output, which will allow you to have a 0.2J/GH mining efficiency, but at lower hashing speed."

So err. Yeah, don't ask.

I'm thinking of getting this thing: http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_374011_-1 since it will allow me to adjust voltage level and isn't too expensive nor inefficient. Also, I ran the numbers on my power supply based on the nominal consumption out of the manual at stock speeds. My PSU is running about 77%. Ouch.

How do you find out if you can adjust the voltage? This thing says "Primary Output Voltage (VDC) 12v".

If you really want to fiddle, go ahead, you might want to have a look at which PSU the other user went with for doing this. I think he needed to get 2 5V~ PSU to do 10V~ to keep efficiency and stuff. Hmm.

But it would be a shame if like other user you try to go to 11.5v and then bam it drops and you can't get any effective downvolting from it. I guess in the worse case this could be the unefficient unit and if you make sure the other unit is v1.91 then you'll have the PSU to undervolt it.

http://www.jameco.com/Jameco/Products/ProdDS/374011.pdf find the column SE-600-12 and go down to "Voltage Adj Range" row. There's a range.

I see, gotcha. A problem someone encountered was that when he went to the lowest range, the PSU went from supporting something like 500W to 100W because the amperage limit also went down with the Volt.

It doesn't seem to say what it will support while at 10V.

Had that problem on this specific PSU?

Turn out the problem with that one was the price. Its being discussed in page 4 and 5. RichBC eventually went with 2x 5v~ to get a range of 9v-11v. Since the one you are interested in work well, but down to 10V.

So its pretty good, if you get it cheap. Others were discussing prices per unit at 230$ and 125$. The link you have is quite cheaper. So look like a good PSU.

Worst case scenario and it's got problem at lower voltages, I end up with a nice high current supply for testing car audio gear I repair. Have to definitely consider this unit.

Well as reported you might be able to go down to 11.5v. Unless something weird happens and you get results that we've only been able to repeat on v1.91. But if not, its not like it can't be used as a "Normal PSU" as well, since it work just fine at 12v. The efficiency isint too bad so, why not.

Gotta finish fixing the most recent batch of dead laptops before I'll have the money for anything more, so anything I can do with what I've got is fair game, but in terms of buying anything else, that's gonna be at least another couple weeks or so.

Yes unlike the S1 & S3 which have Buck Converters that reduce the 12V down to the 0.6-0.8V range needed by the chips, the S5, S5+ & S7 use a string supply for the core voltage. The chips are connected in series (Like Xmas Tree Lights) and so with 15 Chip pairs in the string in an S5 and 12V you end up with 12/15 = 0.8V / chip. Reducing the supply to 9V you then get 9/15 = 0.6V.

1slickvdc your efficiencies at 12V are very poor it could be because of the PSU you are using is low efficieny? You need to understand and sort that before worrying about undervolting. Also remember at the moment "reliable" undervolting has only proved possible with the V1.91 Hash Board.

Rich

Phil that is a pity, but perhaps not a big surprise given the mention of Bitmain wanting to ship some miners with a reduced Hash and the tight spec they have put on the 12V.

However 11.5V represents a Core Voltage of 0.64V so as the spec sheet only goes down to 0.6V that is not bad.  :)

Rich

Had not looked on AliEpress, that unit looks quite nice. As you say some 40A units available this (http://www.aliexpress.com/item/500W-40A-Buck-converter-7V-25V-to-1V-21V-step-down-module-adjustable-and-high-efficiency/1813877363.html?spm=2114.01020208.3.2.UMHW8P&ws_ab_test=201556_6,201527_4_71_72_73_74_75,201409_4) one looks quite nice? I will probably buy a couple to test.

Agreed that parallel connecting carries too much risk as you have to set voltages separately and I have no idea if these will current share?

At some point I am going to try and fully understand which of the differences enable the V1.91 to hash at lower voltages and perhaps come up with a mod for the earlier boards/

Rich

Do you have both? I'm willing to use my skills and available materials as part of your endeavor if you want another unit/pair of hands/head.

I have a broken S5 with v1.5 hash boards that i bought from ebay. Unfortunately it was more broken than I hoped with one board very trashed and not operational, the second board does recognise some of the chips so there is hope. however i have found extracting chips from the first board & planting them onto the second more difficult than I hoped. I have 26 chips operational at the moment but removing them from the first board is very difficult and always an uncertainty that the chip I am removing is actually good. however i will get there.  :)

Rich

Have we tried powering the control board separately from the hash boards? Maybe it has problems at lower voltages because the control board expects one voltage, whereas the hash board is more flexible?

Control board is fine at lower voltages, it's the hash Boards that drop out.

Rich

Back home so have tried editing the "bitmain-freq" line in cgminer.conf

The 3 fields were as I guessed above, Delay, Frequency is just the text that then appears in cgminer and then the Divider setting. 0583 is 75MHz & 0383 is 50MHz

So everything worked as expected with the Frequency text displayed on the Status page and the correct Hash rate was achieved. However there is no gain to be had as the Core Voltage that you need to get down to for these Frequencies to take advantage is lower than the Miner will hash at.

One of my Hash boards will start hashing at 9V (0.6V Core) however the other needs 9.3V (0.62V Core). You can however as described earlier then wind the voltage down. One thing that I have not tried but that is probably possible at these low voltages would be to run with no fan as the temperature is below 30 Deg

Rich

I undervolted one more S5 with parallel DPS-600s and it's happy with 11.3V, 343,75Mhz, 1080Gh/s (avg) and 0,05errors in 20C garage.
I haven't tested used watts yet.
S5 outside in 5-17C with 11,3V don't like speeds over 306Mhz.

Unadjusted DPS-600s give out 12,4V when connected to S1s.

Ordered a Mean Well SE-600-12, should be adjustable down to 10V, so I can give my S5 a shot when that thing shows up and see what it does to power consumption. I'll measure up how efficient it is on something I can use that I know the load of and what not since I know this will be slightly more efficient than that server supply I'm using at the moment. I'll let y'all know later this week where I'm at once it shows up.

Looks to be a nice supply, will be interested to hear how you get on? I have been running on my twin 5V setup for some time now with no problems. Am running with 3 Hash Boards connected, at 250MHz, 10V, 0.67V Core, 456W at the Wall, 1237GHz, 0.368J/GH

Reason I am running with 3 Boards, it that the 4th hash board does not perform as well, so I have put it aside to investigate, but have not got round to that yet... I have ordered a couple more of the Buck converters as I think my preferred solution will be a Server PSU feeding multiple Buck Converters, 1 per Hash Board so that the voltages can be individually set to get the best out of each of them.

Rich

Hope the bucks are well made or you'll start losing a lot between the PSU and the converters by the time they get to the boards. MW has nicer supplies, but I'm too broke to buy any of those (88-90%+ eff.). That's about half the power consumption I'm getting when I run full bore on 2 hash boards at 425MHz, pulls about 830-850W at the wall. (I get $.075 power at night and weekends, so I switch speeds based on power cost)
Can't wait for this thing to show up though.

Some more tests with those 2 buck converters @10.0V:

200.0MHz	661 GHs	0.371 J/GH	245W @ wall
212.5MHz	694 GHs	0.376 J/GH	261W @ wall
225.0MHz	738 GHs	0.374 J/GH	276W @ wall
237.5MHz	772 GHs	0.374 J/GH	289W @ wall	HW 0.0007%
250.0MHz	823 GHs	0.369 J/GH	304W @ wall	HW 0.04%	chain1 44°C chain2 41°C

Actually the S5 needs at least one hour to show an valid average speed.

I havn't tested any higher speeds yet, because the wiring of those buckconverters isn't thick enough to allow me more than a drawing of 15amps through it. Unfortunately, the seller is advertising those converters with a capability of more than 15 amps with a fan mounted -> please, dont do it! I measured a diameter of 1.3 mm = 1.5mm², so 15 amps is the absolute maximum!


Maybe the 40a buckconverter is arriving next week... I'll do some more tests with a proper wiring then.

Edit: Edited 237.5 MHz and 250Mhz speeds, running them right now.

I was initially sceptical about the Bucs when Phil mentioned them, however i have found the efficiency to be very good peaking at 98%. See here for the measurements I made.

https://bitcointalk.org/index.php?topic=1151460.msg12472243#msg12472243

Overall I get about the same efficiency out of a Platinum Server PSU + a Buck as I do from the pair of MeanWell 5V PSU,s which peak at 82%


Rich

Just seen flikflak post, will read it now.  :)

Right, at the bottom line its more or less the same result, using two psu's or bucks. As far as I know, those bucks are quite efficient (looks like they are using FETs or MOSFETs). The efficiency loweres by its delta 12V-10V = 2V delta is more efficient than a lower voltage like 9V.

Edit: But even with a platinum psu with 94% efficiency and lets assume those bucks are @ 96% (0.94 * 0.96 = 0.902) you will end up with 90% efficiency at all.

Both S5s are at 250 MHz:
https://i.imgur.com/8XBxPgP.jpg

100 watts doesnt seem a lot, but it will save you 72KW a month at current speed which is still 7.2 bucks/month with a $ 0.10/KWh plan. I think that money is quite a good investment, I'm gonna ROI those converters in 3.5 months - thanks again!

Yes a nice result. For me with my 15c electricity some form of undervolting is essential as otherwise it is costing me to run an S5. I will be ok until the Halving, but then will have to come up with another plan to keep mining.

I am happy to spend money on PSU and Buck Converters etc as unlike the Miners they are generic and can be used in other projects.  :) With a bit of luck if I move the S5's on at the right time I will get most of my money back.

Not sure what my next move will be, perhaps the S7 will come down in price or I am gathering the bits for a small Solar Mining experiment. I want to try and do it with only a small battery with the mining load being dynamic to reflect the power available. Just an idea at the moment, will start a new thread when I get started properly.

Still want to explore what are the factors that enable the V1.91 to be undervolted and other revisions of the boards not? I feel there may be a bit more to squeeze out of an S5 by fully understanding the effect that changing not just the core voltage but the other IO and PLL voltage, plus the interstage signal / level shifters etc. At the moment it is not clear which of the voltages or signals is the one that causes Hashing to stop?

Rich

From what i understand batteries are expensive and they have a short lifetime? Most people who wanted a 24/7 solar setup ended up seeing that the cost to maintain it wasnt much cheaper than the electricity cost.

Could you instead just feed the electricity back into your electricity meter to make it go in reverse at day and suck it up at night? Assuming you feed back twice what you use at day, it would effectively nullify your usage at night?

I am usually the first to say treat Solar as a completely different exercise than Mining. However I don't want a full installation with feed in tariffs etc. I want something I can play with to prove it can be done in a simple cost effective way, so that I can continue to mine whatever happens to Difficulty, Halving s, BTC price etc.. As I say I am just pulling together ideas, and collecting parts at the moment. I picked up a couple of 255W panels for £100 last Weekend.

I would like to do it completely without batteries however some sort or reservoir is going to be needed, particularly with the UK Weather... My idea is that it will mine only when there is power available and the miner will dynamically change the hash rate to consume the available power.

Anyway just an idea at the moment. I will start a thread when I get going.

Sending the meter backwards is a great idea, unfortunately meters these days, even the mechanical ones have a backstop built in to prevent this.


Rich

I see, thats unfortunate, would of made sense since you'd basically be selling the electricity back to the grid. Please post here with the link when you start that thread. Raising my electricity cap with solar panels would be interesting.

You got a couple of 255W panels for a 100 quid? All together or per panel ? Thats around $155 and a very good price for one 255W panel.

I'm also using solar panels since april 15-> managed to get 2x185W for ~$140.

I'm paying $0.23 per KWh during daytime and $0.13 in the nighttime. So its quite worth it to use some solar panels - on a sunny day they can generate up to 1.8 - 1.5 KW per day and even on a cloudy day those panels can give you 0.3-0.5 KW. With feeding the electricity directly into the outlet with an solar inverter is the most efficient way ~95%. Of course the energy is eaten up by the miner immediately -so nothing goes into the grid (you need a permission for that in most counties). The panels gererated >200KW in the summer season (@.23 thats 46 bucks) so a ROI by the end of 2016 at least mid 2017 is quite possible.

Yes a guy had just installed a 4MW Farm and was selling off some panels that had cosmetic damage. I was late to the party otherwise I would have had a few more. Paid 50GBP each, just minor marks so perfect for the job. They are Gintech 255W each.

The sensible / easy thing to do would just be to plug them up to a Grid Tie Micro Inverter and just plug them into the house supply, but where's the fun in that.  :)

So the outline plan is an Arduino, some Buck Converters, some Hall Effect Current Monitors, a small battery and then some way of Dynamically adjusting the Mining Load. Voltage to the S5 is easy and will just be a Buck Converter with a Digital Pot IC controlled by the Arduino, but I need to adjust the frequency as well?

Anyway I am getting ahead of myself, just the planning and collecting parts stage of the project at the moment...

Interesting numbers on what you can generate with a couple of panels, weather here in the UK will not be that good. I did separately also get hold of a 700W MPPT Grid Tie inverter for 85GBP which I will plug them up to when I am not playing.  :)

Rich

I like your idea with the Arduino... with that it would be possible to change the voltage. Its just too bad that we have to restart the cgminer to change the fequency of the asics and losing one minute for each adjustment. It would be nice to change the asic speed on the fly - like sending a halt state to the asics then change the voltage (up or down), then the speed as well and a continue/resume command to the asics. Hm... sounds too sophisticated, I remember my 386er days as a child and those turbo buttons, I guess that could work.

To the solar panels: Well, the numbers are good, but not as good as supposed to be. With 0.370 KW I should get ~ 400- 480 KW per year (the average output for solar panels here is 1100KW - 1300KW for a 1KWp rated solar panel). The panels are facing to the south, but tweaking the angle to the sun for wintertime can improve a lot.

Edit: Just found a calculator (http://www.theecoexperts.co.uk/solar-pv-calculator) and some avg. specs (http://www.theecoexperts.co.uk/how-much-electricity-does-average-solar-panel-system-generate) for panels in the UK, so according to this, you can ROI them within 1-2 years as well. (£92 per year for 500Wp sounds terrific)

Yes it's a great pity that you cannot adjust the frequency on the fly. One thing I will try is to feed the chips with an external oscillator, they are initially driven with 25MHz which is then converted in a PLL with dividers etc to the final frequency used by the chips. There will be some range that the frequency can be changed over and things will still work, whether it is wide enough to be useful I do not know? However worth a try as that would enable on the fly frequency change.

My other idea on making the load Dynamic is to use an S3 and to switch on or off the individual Buck converters hence adding or removing stages. What I do not know is if you cut a stage & then put it back is if it starts hashing again, however it will be a quick experiment to find out.

What is really needed is some custom firmware with a nice external interface and all of this would then be very simple.  :)

Not too bothered about ROI, but nice to know that it's quite quick, as it's a fun project & should continue to have some use, mining or otherwise for some Years. The depressing thing is that I think just using the electricity generated to power other things in the house and save on electricity cost is better value than using it to mine Bitcoin.  :(


Rich

My power supply showed up and I've been playing with it a bit. Shit, you weren't kidding about the older ones not liking heavy undervolting. At what HWE% should I consider something not plausible as a combination of MHz VS Voltage? My supply can go from 9.3V up to 13.something (although for obvious reasons I'm not going to go higher than my other supply, at 12.65V)

Whatever. If you get 1% HW and you get a better J/GH or better performance, it doesnt matter. Its just that when you go too low or too high voltage for the freq, you will lose performance unrelated to HW.

If you try to go down, just go down to whats stable and the best J/GH, if you go up, you might be able to stabilize 400-425HZ, it doesnt seem possible with stock.

With a good stable PSU, i get very little HWE% however. Under 0.01%

That other supply of mine ran stable at 425, just shy of 1.4TH, but at an expensive 870W since it was running out at 12.65V. For some reason I figured a high % of HWE would actually degrade performance. I did have issues with hash boards not firing up under 11V, but I'll keep playing with it with that knowledge now.

1% HWE is huge for Antminers, at stock loads i get under 0.0001% error rate. But 1% is still just 1% of your hashrate wasted. Its not much if you're looking at a 30% efficiency gain.

But with a good PSU, such as a EVGA G2/GS, seasonics, other high quality OEM, you should'nt really go above 0.1% even if you push it hard and i'd say thats rather minimal. I don't know about the stability of the servers PSU, sadly. But even if its not too clean power, again 1% isint too bad its 14GH at 1.4THS wasted.

Well, at this point I'm playing with that voltage adjustment pot like a teenager with... well yeah. I'm getting some impressive numbers (at least to me running with my old mess of a supply) and I'll eventually find a few good points to put together for data on mine, a V 1.3 board.

Good that is working for you with the V1.3 Board. That is a nice range on the supply can you post up the make & model? As  VirosaGITS says it's all about the Hash Rate you can reliably achieve rather than the HW error rate. That said for long term running I aim for between 0.01% - 0.02% I find at these levels I achieve the expected Hash rate. A few other Hints & Tips I have found along the way.  :)

The expected hash rate for a S5 is 3.3 x Frequency in MHz, here are a few examples.


When you are impatiently waiting for the Hash Rate to stabilise it seems to act like a damped oscillation. If you watch it rise & fall if you note the high & a low of the latest cycle, add them together and divide by 2 it gives you a good idea where it will end up.

When pushing the undervolting I sometimes find that initially the HW error rate is quite high, sometimes as much as 3% or 4% however do not immediately right it off as I find that it will sometimes drop down to acceptable levels.

Measure each board individually as you may find that one board is better than the other. I have two S5 and have ended up swapping the best boards into one system as I can then get the best out of each system. In my final configuration I plan on using Buck converters and may use one for each hash board to enable them to be individually optimised.

When you have some solid results for the V1.3 please post them up. I have a V1.5 Board but bought the system as faulty so at the moment have no measurements.

Rich

The biggest issue I've been encountering so far is that when undervolted it will run and hash for 60 seconds, then at that one minute mark, it will start bitching and stop hashing.

Well this would be because pre v1.91 boards does not have proper volt variation support. RichBC found out thats probably what the oscillator are for.

As such you'll only be able to do very slight under/overvolting.

I only see that feature when I am very undervolted down at levels below 8.9V, however I suspect what you are seeing is the problem of undervolting a board other than V1.91?

As I see that  VirosaGITS has also just suggested.  :)


Rich

Yeah, I just didn't think they were THAT temperamental. Sometimes I can't go below 12.25V or it complains. Why 60 seconds?

I want to add more observations between the different boards versions;

#1 = v1.91
#2 = v1.3
#3 = v1.5

https://i.imgur.com/ByYXQS3.png?1

All the 3 different board like the cold. v1.91 is showing 0%, its at 11 HW atm. v1.3 and v1.5 behave the same way, i don't know the differences between the boards but it does not seem to be performance related. The v1.91 does perform marginally better.

#1 and #3 is powered by the same, brand new EVGA GS, PSU.
#2 is on a EVGA G2 1k

Difference of v1.3 and v1.5 at these temps vs hot 60c~ is 0.0035%~ vs 0.006%~

Yes in general I would expect performance to be better when cold than hot. I have however as detailed in my earlier post sometimes seen a high error rate when first switched on that then reduces. This may or not be temperature related?

Not sure that I fully understand the table above? What was the voltage for the tests? Would be good to have some column headings on the table?


Rich

Stock. I don't have undervolt or overvolt capabilities, this show the difference between the boards. The 0.006% is over a long period of time, so its temps. Even though it does take a while to stabilize the HWE% over time, it does go down as well, not just start up. The S4 is like that. HWE tend to go down a bit after start. But that just seem to me like most ASIC like to start with some HW.

Here is the header, not that it will give much more information;
https://i.imgur.com/usPSG94.png?1

This just show that v1.91 has some capability to stabilize the chip's voltage slightly, which may be what the oscillator were intended to do when put in place. Enabling us to feed it down/over volted current is probably a side effect.

The input voltage is the same for #1 and #3 (and #2 is effectively the same too but #1 #3 has the same source and same reading) yet they have different HWE%. The chips are the same, controllers are the same, etc. You know better than me what that leave as reasons.

Yes interesting numbers, why id 5S3 running at half speed, is it just a single  board?

 I have come to the conclusion that there is a lot of variance between Systems and also between individual boards. I have running at hope two S5 at 250Mhz, one system undervolted to 10V the other running at 10.3V. I have put the best 2 boards in the first system. There is however quite a variance in the HW Error rate & the board temperature. I will post up the numbers when I get home.

Rich

Ok here's what I have been running with for the last couple of Weeks.

http://www.slotforum.com/forums/uploads/1444996927/gallery_2150_2322_146958.jpg (http://www.slotforum.com/forums/index.php?autocom=gallery&req=si&img=77130)

It's a single S5 Controller with 4 Hash Boards connected. 250MHz with the best two Boards undervolted to 10V & the less good pair at 10.3V. Am using the pairs of 5V Meanwell PSU's to power it. Hashes at 1650GH/S and takes 615W at the wall giving 0.373J/GH.

It's just in my target HW error rate at 0.222% but more importantly the actual Hash rate matches the Theoretical Hash rate. The boards are arranged in the systems by how good they are and you can see that the best two run at 35 & 37 Degrees and the worst two at 41Degrees. Will probably run with this setup until I replace it with individual Buck Converters for each board, assuming they give a better result?

Rich

Correct. I bought half a S5, which is why i'm trying to find a working S5 blade to slot it in, it would be pretty simple, but so far no luck.

It look like the boards, at factory setting do perform nearly exactly the same however, but i do not know why when "we" push them down or up you start seeing differences as i'm not very knowledgeable about electronic fabrication.


It could, i'm not sure about the variation in temp, i think it just depend on where the sensor is on the board, if its closer to intake, it will read lower even though overall the board is at the same temperature as the other.

However i noticed that if you don't put two fans, one of the board is actually fairly hotter than the other, and if you put them on the side, the top board seem to heat up more, probably because of thermodynamics... i mean the how air likes to go up.

So i played around with some numbers to the result of undervolt of the S5 to profit to see what kind of numbers we could expect in this difficulty range.

http://www.mediaboxauthority.com/antminerrates.jpg

So as we can see depending on your costs undervolting the S5 could end up costing you profit.  So I would be careful about when and if undervolting will result in greater profits.  In my case it would not be until difficulty rises 30% and at that point then applying the mod would add benefit.  Just a word of caution that not all things come out in theory as they do when you compare the data on paper.

Yes agreed I have a spreadsheet and at any point in time you have to adjust the Frequency for maximum profit. However even at the standard clock frequency of 350MHz I can still undervolt to 11.1V for greater efficiency and profit.

My electricity in the UK is $0.15 and at current difficulty I am now running at 300MHz and 10.7V

Rich

The 40a buckconverter arrived yesterday. I've ramped up the voltage a bit:

@275MHz	859GHs	@10.50V	349Watts @Wall	0.4063 J/GH	HW 0.07%
@300MHz	897GHs*	@10.50V	378Watts @Wall	0.423 J/GH	HW 0.15%
@300MHz	949GHs**	@10.80V	397Watts @Wall	0.4188 J/GH	HW 0.06%
@312.5MHz	949GHs	@10.80V	414Watts @Wall	0.4362 J/GH	HW 0.10%
@325MHz	966GHs	@10.80V	429Watts @Wall	0.4430 J/GH	HW 0.14%

*one board dropped after 30 minutes, it was around 912GHs before that happend

**I doublechecked that, it's valid. The second run (doing it now) is @ 955.5 GHs (avg. after 33 minutes). Its nice to see, that even a slightly higher voltage can increase your efficiency as well. My guess is, that a lower HW error rate might be the reason for that -even if it is negligible @0.15. So finetuning it is an eminent factor.

Yes I don't like running with much more than 0.05% HW error and aim for between 0.01% to 0.02% at which point I seem the get the theoretical hash rate. I usually find at 0.1% and above the hash rate drops below what you expect, although as I have said before at power up I sometimes get quite a lot of HW errors so you have to let that rate work through. Remeber you can calculate the expected Hash Rate by multiplying MHz x 3.3

I have also just taken delivery of a couple of 40A Buck Converters, had a quick check and they seem ok but have not connected to the S5 yet. Are yours the Black metal case potted ones with 3 Brass terminals and the gold heatsink?

Been playing with the R1 so just letting the S5 which is on the Meanwell 2 x 5V PSU's run at the moment, but will probably try the 40A units Tomorrow.

Rich

Yes, I got them too. It looks like the brass terminals are made of copper (or are copper-like material, could be also an copper/zinc alloy =bronze :D -you never know) and the package has been shipped from singapore.

I did some more tests @200Mhz with lower voltages.

black = 40A buck converter (so far there are no issues after 12h)
blue = 2x 15A buck converters (no issues after 1 month @ 24/7)

@100MHz	270GHs	@08.93V***	96 Watts @wall	0.3555 J/GH	HW 0.08%
@100MHz	328GHs	@09.80V	118Watts @wall	0.3598 J/GH	HW 0.0060%
@125MHz	285GHs	@08.93V***	119Watts @wall	0.4175 J/GH	HW 0.12%
@125MHz	371GHs	@09.05V	123Watts @wall	0.3315 J/GH	HW 0.071%
@125MHz	401GHs	@09.80V	144Watts @wall	0.3591 J/GH	HW 0.011%
@150MHz	437GHs	@09.05V	147Watts @wall	0.3364 J/GH	HW 0.11%
@150MHz	487GHs	@09.80V	170Watts @wall	0.3491 J/GH	HW 0.03%
@175MHz	546GHs	@09.80V	196Watts @wall	0.3590 J/GH	HW 0.06%
@200MHz	632GHs	@09.80V	221Watts @wall	0.3497 J/GH	HW 0.06%
@200MHz	663GHs	@10.001V	245Watts @wall	0.3695 J/GH
@200MHz	657GHs	@10.80V	267Watts @wall	0.406 J/GH	HW 0.0027%
@250MHz	810GHs	@10.05V	305Watts @Wall	0.3766 J/GH
@275MHz	859GHs	@10.50V	349Watts @Wall	0.4063 J/GH	HW 0.07%
@300MHz	897GHs*	@10.50V	378Watts @Wall	0.423 J/GH	HW 0.15%
@300MHz	949GHs**	@10.80V	397Watts @Wall	0.4183 J/GH	HW 0.06%
@300MHz	972GHs	@11.10V****	428Watts @Wall	0.4403 J/GH	HW 0.008%
@312.5MHz	949GHs	@10.80V	414Watts @Wall	0.4362 J/GH	HW 0.10%
@325MHz	966GHs	@10.80V	429Watts @Wall	0.4430 J/GH	HW 0.14%
@325MHz	1047GHs	@11.1V	465Watts @Wall	0.4441 J/GH	HW 0.028%
@337.5MHz	1071GHs	@11.1V	482Watts @Wall	0.4496 J/GH	HW 0.047%
@350MHz	1090GHs	@11.1V	502Watts @Wall	0.4606 J/GH	HW 0.096%

*One board dropped after 30 minutes, it was around 912GHs before that happend
**I doublechecked that
***One board dropped or didn't even start
**** Voltage drops under load by 0.1V (11.2 without load), Amps @36.25
Sweet spot so far

more tests at lower/higher volts soon

Edit: lower frequencies and voltages -> 9.05V seems to work fine and stable

Nice set of results and quite consistent with mine. I can't start up with less than 9V although once hashing I can then wind down to about 8.4V although it's a bit prone to then losing one of the boards.

I have connected the 40A BC to one of the S5 instead of the 2 x 5V Meanwell Supplies. It's set to 10V running at 250MHz and I am seeing an on load voltage change of 0.2V whereas it was 0.1V with the Meanwell supplies. I will also try some higher Frequencies, but need to hook up another 40A BC to the other S5 first as I am running them on a single controller board.

Rich

I just tried 250W @ 10.4V and the voltage dropped down to 10.258. I didn't give it enough credit, maybe because of the crappy uni-t 61E I'm using. Also the fequencies from 325 and above to 350MHz have been tested for only 10 minutes (voltage drop was around 0.3V and much more important the ~43 amps @ 350MHz).

My best revenue is between 250-275MHz at this difficulty, exchangerate and costs for electricity, so there is no need for the sweet spot yet and one converter for each S5 is good enough for me.

Well, there is still some room for finetuning...

Has anyone dug deeper into these things, like seeing how the power or signal chains look on a scope at lower voltages?

It's on my list of things to do.  :) Part of the hold up is that my two working S5's are V1.91 which can be quite successfully undervolted. I have a V1.5 but it was a failed unit I bought of ebay. I have been taking BM1384 chips off the completely failed board to repair the better board and currently have 26 of the 30 chips working.

However a couple of things are hampering progress. First is that I only have a hot air gun and it's not really up to these QFN chips, so I will invest in a proper infra-red rework station. The second problem is that I am always uncertain when I have removed a chip if it is a good chip, which combined with the lack of a rework station makes progress slow. I have also ordered a qfn test socket and plan on making a little test jig for chips so that I only use good chips in the repair.

Anyway when I get sorted and the board is repaired I plan on making some careful measurements as the voltage is reduced, as well as exploring the value / part played by the multiple oscillators and the alternate LDO Regulator power scheme used in the V1.91...

The other interesting snippet to throw into the pot is that in playing with the R1 which has a single BM1384 the Core Voltage that it will reliably hash at at a given frequency is quite a bit lower than the S5, so this is probably because of the simplicity of a single chip, which does not rely on chained signals or voltages, but it is a clue that signal integrity is key to an undervolted S5?

Rich

I'd think in a system like this that certain things, such as the signal and controls have very little tolerance, and given the undervolting, maybe the signals aren't moving around at a high enough voltage to be picked up by other parts (reducing voltage possibly reducing output level of some given component).

What about hooking up a non 1.91 to a scope just to see any differences in inter-component signals, that been done yet? I've got a new scope showing up soon here and if you want me to check some things out I can, since I've still got that older version one here.

Yes well worth doing. I had a quick look but came to no conclusions. Just remeber that you need to move the ground probe to the ground on each stage as you move up the chain. Also only have one measuring device connected at a time to avoid the risk of shorting stages with different grounds.

As well as the signals the voltages available for the LDO needs to be checked. A quick bit of maths I did indicated that the LD0 gets a bit close to it's limit at lower voltages. Another "feature" that complicates things is that the voltage needed to start hashing, at lower voltages, is higher than the voltage to maintain hashing.

Rich

Somewhat like starting capacitors on motors (although current vs voltage here), just need it to get it going, then you can reduce the voltage?

If you want to point out a few places for me to start and what to look for, since this will be the first time I've ever dug into these things, that would be a definite bonus. Halloween makes a damned disaster of downtown Madison, so I'll definitely be stuck at home doing nothing that night and I'll gladly take some time digging in.

Also a quick run-down on the specifics of these hash boards, what certain sections/components are, etc. would definitely speed things up on my end, since I'm mainly an analog guy (I do amplifier repair, mostly)

Ok I can't spell it all out but...

Have a read through this thread, this post with pictures of the boards and a few notes is useful.

https://bitcointalk.org/index.php?topic=1151460.msg12164839#msg12164839

Download the BM1384 data sheet, shows the pinout and other details
https://bitmaintech.com/support.htm?pid=00720141220132903742H2RLy6C40630

The LDO regulators that supply the voltage fpr the IO Voltage & the PLL are key. They are marked 4VK4 & R18 for the later stages.
Do a google search on LN1134  and SPX5205 for data sheets on these.

Find your way round the board. As a clue the bottom stage in the chain is at 0V and is directly below the 18 Pin data connector. The chain then goes round anticlockwise with the top stage being at 12V.

Lot's more I could say but that's enough for now.  :) Just be careful when making measurements remember the ground for each stage up is the +ve for the previous stage. Finally set the clock right down to 100MHz to start with reduces the consumption & heat when working on the board.

Rich

I wouldn't expect nor ask you to explain the whole thing to me, just pointing me in the right direction to get started, which you've done already with that other thread. I'll let you all know when the scope shows up and I can start screwing around with it, and once a sale of some more BTC finishes transferring out, I should be acquiring that V 1.91 I mentioned before.

Thanks for the links and info.

I may have asked this and forgotten, but which "batch" did the v1.91 boards come from? I've got the capital to pick up another one to experiment with and I want to make sure I end up with the right one, given many eBay sellers don't know their board version numbers or haven't responded to my inquiries.

Mine came from the used batch, but any miners after a X date (listed somewhere in the thread) are v1.91. The problem is probably that at some point there was a mixed batch and also primarily the fact that they are also no longer for sale.

So your best bet might be to find sellers of the used hardware and ask them if their S5's has v1.91 PCBs.

I've been asking and many don't reply, others "don't know", and the one seller who confirmed 1.91 sold out before I got my money. Keep digging I guess. Thanks. I'll update when I get something.

What about the v1.9 boards? Found one of those and remember the mention of those somewhere earlier in the thread.

V1.9 boards have provision in the layout to convert to a 1.91. That is additional Oscillator modules with ascociated components and removal of the LDO regulators and feeding power directly from the stage above. See this post for pictures and some more info.

https://bitcointalk.org/index.php?topic=1151460.msg12164839#msg12164839

The oscillator in particular is not an easy addition unless you are experienced in and have the equipment fore surface mount components.

However we have still not proven if one or both of these changes are responsible for the undervolting ability of the V1.91


Rich

People are lazy, to get a reply i had to link a picture to where to get this information every time. (Top right corner of each PCB, under the bitmain logo + enter url here) then i got replies easily.

With the BTC price value going up however, i won't be undervolting these babies for a long time.

yeah, it has hit the point I can afford to run mine 24/7 which averages out to 13.8c/KWh, even with this crappy supply I've got. Still want to score more efficiency if I can, especially if I can figure out WHY some of these machines are cutting out at certain voltages, but something dawned on me earlier...

LDO's are mentioned for the older boards, and they switched regulation methods. Is this a game of losses? Instead of using LDO's, which in my understanding, are still linear devices, they switched to a switch-mode type regulation which can be set dead on. One of my older ideas was that the signal wasn't going through at a high enough level to be considered "high" or "low" to whatever receiver was getting them... Also still haven't checked things out on the scope yet either for whatever reason.

On all the earlier boards there are LDO's that supply the 1.8V for the IO & PLL part of the ASIC, not the High Current Core Voltage that comes from the Series connection of the Cores.

On V1.91 they have completely done away with the LDO which used to take it's input from the stage 3 levels up the chain and now they directly take the voltage from the core voltage of the stage above.

Not the best of pictures but here is V1.9 on the Left, V1.91 on the Right

http://www.slotforum.com/forums/uploads/1447019482/gallery_2150_2322_8730.jpg

So this is the bottom stage in the chain, you can see on the Left U6 which is the LDO, then on the Right U6 is not fitted but R231 is fitted, this is a zero Ohm resistor and connects the Core Voltage from the next stage up the chain directly to the IO & Analog PPL circuitry, the Digital PLL retains the voltage divider to drop the voltage to half of the Analog voltage.

The LDO is however retained for the top stage of the chain, as there is no stage above it,  :) fed from the 14V Buck converter on the Top Right of the PCB

Rich

I'm about to clean out the cat fur from my V1.3 S5, would you like some high-resolution images of the boards disassembled for any reason?

I have pictures of most of the Rev's but some are poor so yes one good high res picture of the component side of the board would be good. At some point I am going to start a guide on Troubleshooting and Repair and that might be handy.


Rich

Okay. In the lab on some good gear, so if y'all can reply quick enough I can do some interactive testing.
Something I did notice when I lower the voltage is I lose the clock signal that's observed on CLK01 directly underneath the ribbon cable. That signal is a 25MHz (mostly) square wave at about 3V. If I reset cgminer (using the apply settings button in the interface) after lowering the voltage, I'll lose the clock. If I adjust on the fly, the clock stays going at a lower voltage. I'm running the ASICs at 300MHz right now, down to 11.0V and still have the clock and hashing at 975GH/s with a .02% HWE.

Here's the clock signal I lose if started below 12V at any frequency, but seems stable above 10 something volts.
http://wavemadison.net/mine/s5_clock.jpg

Not sure to what degree interaction will be possible, just up in the UK, it's 07:40. A few comments.

So that clock signal is on the output of the bottom ASIC in the chain (the one with the Y1 oscillator at the centre of the board) where it feeds the clock input of the next chip up. As a matter of interest the 4 pads to the left are also to monitor the signals between the pairs of chips.

On a v1.91 board of the four I have measured at 300MHz the voltage for an acceptable HW error rate varied between 10.4V & 11V. You might want to cut the frequency right back for low voltage testing to 125MHz as this gives more scope for voltage reduction with a low error rate. It will of course make no difference to oscillators stopping. At 125MHz my four 1.91 boards had acceptable errors between 9V & 9.7V.

So oscillator stopping is not good, can you confirm the minimum voltage that you can restart cgminer and have a clock? Also worth measuring the bottom Node Core voltage (Across the big capacitor C17)  for reference?


Rich

I have run a few quick tests and I think you are onto something with the oscillator not running. I have a v1.3 Board which I am repairing. I have bypassed the top two stages as there is a faulty ASIC or two there, but otherwise it is operational and I am operating it at reduced voltage so the the Core Voltages are correct.

So I have reduced the voltage so that I get to the point where it does not start hashing and like you the key is that the oscillator is not running. It typically runs briefly and then stops. I think there are other factors preventing undervolting of the earlier boards, however this is definitely one of them. I am wondering about fitting a separate oscillator powered from the 3.3V as opposed to relying on the oscillator circuitry in the first ASIC?

Another "feature" I want to explore is that I have been monitoring the Core Voltage on the first stage during power up. For some reason it is low / lower than the other stages (0.45V v 0.7V) when the oscillator is not running. There is some variance between the other stages but not as much as this? This may not be helping or may be a red herring?

Another observation is that when the oscillator is running it keeps running during a cgminer restart. However if the oscillator stops it will not restart when the voltage is increased, you have to restart cgminer to get it going again.


Rich

At the moment this is the only thing I can process a little farther. Maybe cgminer sends out an instruction of some sort, triggering the oscillator to do its thing, and if it's already running and it does a quick reset, it's so fast we're not going to see it unless we're looking closely enough and know what to look for and when. I think setting up an oscillator to run off of a dedicated supply somewhere, the control board, an individual linear regulator, something along those lines?

The LM75A Temperature sensor runs on 3.3V which comes from the Controller Board, that is a convenient place to pick up a voltage for an external oscillator test, not sure if I have anything "in stock" or if I will have to buy something?

As you were.....While typing this I decided to check the output of the oscillator itself and it keeps running at the lower voltage, so it's already ok.... So this means that the reduced core voltage for some reason stops the Clock Output from the first chip not the oscillator itself?

Rich

Not sure. I got distracted and ended up leaving the thing running for about 20 minutes at ~11V (300MHz) and the clock stayed going for quite a while then apparently out of nowhere, it started beeping, and I looked over to see it off. Not sure what might trigger it to go off.

If it is not hashing after a few minutes the miner will beep, the same as if it has lost Internet connection. Yes I have found if you are on the edge of working it can stop for no reason, also I have had one board stop & the other keep going.

I think this is really a game of finding a stable voltage for some sort of infrastructure-like device, such as the oscillator. Question is: is it just the oscillator or are there more components at play here?

I think this is one of those problems where there are multiple factors in play, always more difficult to sort. Keep at the back of your mind when working on this the key changes identified between the earlier board & the V1.91 that does allow undervolting.

1) It has multiple oscillators every 4 Nodes up the chain.

2) The 1.8V for the IO stages & PLL is in the earlier versions derived from an LDO regulator fed from the Core Voltage 3 Nodes up the Chain, wheras V1.91 takes it's voltage directly from the next Node up the chain.

I have already checked that the LDO Regulators continue to supply 1.8V when the supply is reduced and they have plenty in hand for a voltage way below where we are going to.

A theory I have is that having it directly connected to the stage above means that the IO Voltage will track down with the Core voltage and the ASIC "likes this"? My other theory is that it was merely a Bitmain cost reduction unrelated to anything else?

I think the problem we have here is not the oscillator stopping but the PLL that converts to the higher operating frequency not locking?

Rich

I'm slightly against the PLL Idea, since I believe that's part of the ASIC, is it not? Therefore it would be based on, most likely, the digital voltage which comes from the LDO, and since that's stable... I think if we can figure out how the oscillator is triggered (why it fires up and when) that might help a little bit. Does the power from the LDO's go anywhere besides the ASICs?

Yes PLL is part of the ASIC and yes the ASIC IO circuitry and the Digital / Analog parts of the PLL are powered by the LDO. Each Node / Chip pair has it's own LDO that draws it's input voltage from Core Voltage of the Node 3 chips up the Chain.

So at 12V supply when each node is seeing 0.8V then the input to the LDO sees 0.8V x 4 = 3.2V. The LDO gives out 1.8V for the PLL Analog Circuitry and the IO Circuitry. There is then a potential divider that drops the voltage to 0.9V for the PLL Digital Circuitry. That is all each LDO supplies, and as I said earlier there is plenty of headroom on the input voltage to the LDO for any sensible supply voltage reduction.

The oscillator itself seems to be fine at all voltage levels and starts without problem, the problem is the Clock Output (Pin 19) from the bottom ASIC that you have monitored at the CLK01 Test Point. If you look at the 25MHz oscillator itself it is a nice sign wave, whereas the 25MHz clock signal at the test point is not that nice looking and has obviously been through more than just a buffer?


Rich

Important update to the above and back to the oscillator being the problem  :). I carefully checked the oscillator again and at the point that the Clock Output CLK01 stops although there is still an oscillation it's amplitude drops and it's unstable.  Also it is at that point that the core voltage drops from 0.7V to 0.48V. However If you increase the voltage then the oscillation does not become stable again until cgminer is restarted. I suspect a reset command is sent to the ASICS, also I am sure commands to set the PLL dividers will be sent.

So I think it is worth trying a separately powered oscillator.

Didn't have time to read this entire thread. So basically there is no way to mod the S5 by reducing the resistance like on the S1/S3 ?

Only way is to supply 10V from a power supply?

Can't you put a resistor between the PCIe connection to drop the voltage down to 10V from the PSU's 12V or is there some kind of protection built into PSUs ?


http://www.gtsparkplugs.com/images/12Volt-LED.gif

Simple answer, no you cannot do simple resistance change as is S1/S3.

Reason is that there are no DC-DC converters in the S5, the ASIC's are connected in a string so the only way to reduce the voltage is by reducing the 12V supply. Resistor on the input also not practical as the volts it drops will vary with current, and will be dissipating significant power which will negate a lot of the saving. You would need to use one of the options for voltage reduction covered in this thread.

Rich

My new (hopefully) v1.91 is on its way, or should be. Something dawned on me. The difference between the v1.9 and 1.91 was very small IIRC, could a 1.9 be modified by someone with the right equipment and skills to work like a 1.91?

Yes could be modified. There are 3 crystals with a few discrete components to add and then lift the level shifting diode on those stages. Then remove the first 14 LDO Regulators and fit a zero ohms link to connect the IO voltage directly to the stage above.

So if you can solder small surface mount components then relatively simple.

Rich

SMD's aren't that bad. We'll see if this board is a 1.9 or 1.91 and see what happens from there. Maybe we'll have another project on this thread.

Also forgot to post this up... High res shot of the 1.3 hash board

http://wavemadison.net/mine/s5_1.3_hash.jpg
http://wavemadison.net/mine/s5_1.3_hash.jpg

dammit, how does everyone embed these images?

I got my hand on a 1.9, was surprised since it take over 393.75 freq effectively, running 400hz at 1.32+ TH/s with virtually no HWE, all the others cap at 393.75hz at 1.29-1.3~.

I've been running my V1.3 at 400MHz with .013% HWE with that monster PSU.

I tried those IMG tags and that image proxy/invalid image thing is what comes up

http://wavemadison.net/mine/s5_1.3_hash.jpg

Ah i see what you mean.

I use this format normally it work;


https://i.imgur.com/l45Vt4I.jpg

Something might be wrong with the picture itself. Since this work;

https://i.imgur.com/3UjmfRn.jpg

Might be the images are too large or too high of a resolution. Damn phone shoots like 16MP with a 5MB file.

My "brand new" S5 v1.91 is here, including a nice 80+ Gold PSU for my 1.3 to bring those consumption numbers down. I'll poke around with this and get some numbers on my 1.91.

Its very interesting to "poke around" i have 1.1, 1.3, 1.5 and 1.9 and 1.91 mixed in 4 S5 and oddly enough, i have no idea why, but they all cap at 393.75hz on high quality PSU, 375hz on lesser psu (Like gold raidmax)...

Except the 1.9, that one do 400hz with no HW, getting 1.32TH/s while all the other cap at 1.29~TH/s. I don't get it. And i suspect i could push it a bit further but i'll wait a little for the motivation to do further voltage testings. I dont get it because its not the PSU having higher voltage itself. When i swap PSU used by 2 S5, they still get the same hashrate/HWE%.

At least i know that EVGA G2 and GS have consistent top notch clean power, same with the server PSU's i got from Quakefiend.

I'd just like to understand why the 1.9, i assume, have higher core voltage than all the others. It is my only guess as to why it is stable at higher OC.

My 1.3, using that DPS-800 PSU (which runs at 12.65V loaded) can run 400-425MHz stable and less than .1% HWE most of the time. Runs around 1.3-1.4TH at that speed. Gets seriously hot and needs to run the fan balls out even with a window nearby (outside ambient temp <10C). Just put a NEX750G on it and brought it back down to 350MHz, nice and cool at 50C, although running a .025% HWE, which seems high at stock speeds.

I'm getting some numbers on my 1.91, although I don't know if any of y'all tried undervolting at stock speeds, and speeds near that. I'm starting at 350MHz and working my way down with voltage and core frequencies.

A note on my methodology here: I'd mine for no less than 10 minutes at any given freq/volt combination, then reduce voltage (restarting cgminer at each step-down) until GH/s rate reduced significantly, then bring voltage to last working level, and then drop frequency. Lather, rinse, repeat.
Temps are with fixed "30%" fan speed, ~20C ambient.

http://wavemadison.net/mine/undervolt1.png

A nice set of numbers and very consistant with what I have measured. I have found that J/GH continues to improve as you drop voltage / frequency with the absolute best J/Gh being between 150MHz & 175MHz.

The other thing I have found is that each hash board in an S5 gives a different result so as you reduce the volts it is initially just one of the boards that is responsible for the increased HW error rate. It's worth  doing some measurements on individual boards to better understand your system.


Rich

I've noticed hash rates roughly half of normal at certain combinations, so I must have one board that misbehaves before the other. Too bad there's no tattle-tale on which board.

If one board drops out completely usually but not always the Red led on the board will go out.

Rich

Yeah. Just didn't seem like a normal dropout. Lights were both on. Hashing very slowly, at roughly 50% power. Strange.

So how are you are running these undervolted? You have some special PSU that runs at 10Volts? Aren't those noisy and expensive?

I have two systems. First I have a pair of Meanwell 5V PSU's in series, these allow me to adjust between 9V & 12V

Second I have a Server PSU with a Buck Converter on the output, and can set any voltage with that. Neither solution is expensive or more noisy than other PSU. Various pictures & information in this thread.


Rich

Anyone to use a regular computer PSU ?

You can do it but you'll have 12v output so you will need to use buck converter and i don't know if you can make these adjustable. Meanwhile you can get server PSU with an adjustable volt pot so you can get exactly the volt output you need without going through a gadget.

Which server PSU have an controllable output voltage option?

The 12V -> Buck Converter for every PCIe port is just going to create a huge mess with alot of wires.

My main focus is to just make the S5 quieter. The aftermarket fans are too expensive.

With a 40 Amp Buck Converter you only need one.

http://www.aliexpress.com/item/500W-40A-Buck-converter-7V-25V-to-1V-21V-step-down-module-adjustable-and-high-efficiency/1813877363.html

Rich

How would you hook that up to both the S5 blades?

You just connect all the 4 PCI-e cable ground to the ground and the 4 PCI-e cable +12v to the output +volt. Or 2 PCI-e cable then use 2 splitter if you want to connect less things directly on the buck converter. Same principle apply for others converter, which might be a good thing to keep in mind since that one in particular seem out of stock.

My favoured solution would be an adjustable Server PSU, trouble is not much information exists on which ones can be easily adjusted. The RC guys are very hot on voltage adjustment but they are mostly interested in increasing the voltage. This is often easier as you can use an adjustment to the sense voltage to trick the PSU into increasing it's voltage.

The Bitmain PSU has an adjustment and has been reported to be adjustable from 11.5V to 12.6V This is useful but not really low enough for max underclock.

I have played with an HP DPS600, this can be mad to go 10.56V but unfortunately as you turn the volts down the Power you can draw drops and again is not ideal. (data somewhere back in this thread)

I am sure there will be some wide range adjustable Server PSU's however at the moment I do not know which ones? Which is why I have used a separate Buck converter, not ideal, not as efficient, more wires, but very adjustable and enables you for a small additional cost to use an existing PSU.


Rich

Do you mind posting a photo or your setup? Just want to see if it looks messy

Away from Home until after the new Year, and not using the Buck Converter at the Moment as with the improved Exchange rate I am running the S5 flat out.  :) However I will put it together again and take a photo when I get back.

Rich

can 2 s5 boards be set up in series maybe? the reason im asking is my solar panels are putting out 20 volts.

Would not do this as it will cause all sorts of problems with grounds & the controller interface etc.

I would advise using a Buck Converter to convert the 20V to 12V, however you will also have a problem when the sun goes in and you loose the Power?


Rich

Would not do this as it will cause all sorts of problems with grounds & the controller interface etc.

I would advise using a Buck Converter to convert the 20V to 12V, however you will also have a problem when the sun goes in and you loose the Power?


Rich
[/quote]

rich thank you for all your input on this subject here, in the s7 thread and over on https://fanbitcoin.com/index.php?topic=771979.0;all about the s3

i figured the controller would need to be kept at a lower voltage as for the cloud passing by issue i have 7.5KW / 50 153 watt panels im trying to use for mining and i should have plenty power to do a little buffering.

yes i have a couple of 12 amp buck converters coming in tomorrow but the 40amp one linked here isnt available any longer and other high amp ones for a cheap price has been hard to find.

as for evening hours i plan to switch to house current for profitable miners like the s7 and on that note can they be underclocked / under volted the others7 thread seemed like no one has tried...  in the s3 thread the pencil mod / adding resistors to change the buck regulator is cool and all but what you did using the digital pot is more what im thinking and FYI my C1 i just lowered to 650 in the advanced tab and 150 clock and it like .63 so kinda intresting...  

Happy to have been of some help. Would it not be easier to just have  grid tie inverter and run the Miner in the conventional way, and then just keep track of the Solar Power you have generated & Power off the Miner for the right amount of Hours so that you were only effectively using solar power for mining?

Have not seen S7 Undervolted successfully yet and results will depend on batch. The 162 chip versions will be able to accept reducing the voltage as they are pure string design. The 135 chip systems have a Buck converter controlled by a PIC microcontroller, however although there has been some discussion noone has reported doing the work to fully understand the Pic / Digital Pot arrangement and come up with some Mods. which I am sure will be possible and enable undervolting.

Unfortunately I do not have an S7 otherwise I would play with this. Which batch / version do you have?

Rich

I think i have a s7 batch 8, IDK yet for sure but it came clocked at 700... i have it, 2 s3's, a C1 and a s5 that im clueless what board is in ATM too.
yes a gridtie does make a lot of sense but my panels aren't UL approved and here in the USA they have to be is my understanding.

BTW in s7 batch 10 they say Rated Voltage: 11.60 ~13.00V

so far the s5 looks to me like it may be my best option to burn the 7.5KW undervolting using 2 12 or 15 amp buckconvters each connected to 1 board.
do you have any idea what will happen if the amps needed aren't available?

yes 700MHz will be batch 8 or 9, with 135 Chips & the Buck Converter.

Not having enough Amps is not a good idea. The voltage will drop and the Miner will stop mining, then the voltage will rise again, miner will reboot and the cycle will repeat. Could easily harm the miner.

Rich

can any of you DC power experts :) tell me why when i hook up a buck converter outputting 12 volts and what should be plenty of amps my meter goes black and the board isnt powering up, im even running the control board and the other hashing board off a real power supply and turned it on afterwards...

i tried another brand of buck converter too.
only thing i can figure why my panel meter goes black is it's sucking the voltage down under the 6v min but why is the billion BC question.

Thanks in advance.

What do you mean by "meter goes black"? What range have you got the meter on / is it ok measuring other voltages?


Rich

thanks for the quick reply rich, im such a idiot!!! it's just a panel amp / volt / watt meter that has a range of 6 to 100 volts and 100 amps i think but i found my problem, i started thinking maybe 1 of my 3 wires going to each side of the molex connector may be swapped around and no i was dumber than that!!!

i had the positive and negative reversed and i cant believe i didnt burn out the board but im testing on a s3 b4 i get brave enough to try my s5 or s7.

it's running fine ATM on a drok 8-12 amp buck at 150 clock since this buck is so low amp but at least it's not a dead short now LOL

Good result, glad nothing got damaged, we all have these moments.....


Rich

Well I can tell you that if you swap the +/- on the S7 board you will indeed get a magical puff of smoke and need to buy a new one...   Not that I'd have any first-hand knowledge of this. ::)