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Objective:

• Reduce jet engine to crying baby noise levels

Hypothesis:

• The cases are constructed using perpendicular nut-bolt things. Great for small scale quick production, but not great for a tight seal.
• These connections have quite a large open gap at every screw, on all size.
• If you feel over the gaps, there is a significant amount of airflow [*read pressure] leaking.
• This is not useful pressure, we want to be exhausting through the heatsinks and not through these random holes - they serve no cooling purpose.
• =fans are spinning faster than required to get the same pressure.
• Airflow through these holes will also be much more turbulent and so will also be generating some of the frequencies we hear.

Method:

• Tape those badboys up, simple electrical tape would do it.

Results:
*pending*. The only unit I have in stock at the moment is reserved for an auction, but if that falls through I will give it a go. I don't have a temperature controled room so I can't make it a scientific test though.

Conclusions:
*pending*



tldr: Case has holes at the screws, lowering air pressure inside. Fans spin faster to compensate = more noise than required.


EDIT: V2 ready, see below.

interesting

getting mine soon. so i will be doing some testing or small mods of my own.

will update this thread with my progress once i get it.

Anyone have any results?

I can't imagine this would make a significant difference.

I don't think this will make any (significant) difference.
One of the problems in my opinion is the huge "gaps" between heatsinks. A lot of air is running without doing any cooling. The air coming out is "cold", but the heatsinks are definitely "hot" because the plate of the case to which they are attached is "hot".
I intend to put something to force more air on the fins and PCB surfaces. But I have now bigger problems with my avalon :(, so I'll delay this.

The other two fans are compensating for the one pointing directly at the cables. Freaking whirlwind in there. Those screw holes may actually help with pressure release.

Going by the pictures of these things, I'd be constructing air guides using card.  Build a tunnel from each fan to the heatsink, and cover the open top of the sink to force the air though the heat sink.  It's basically the way 1U and 2U servers are cooled.

In Avalon3 there are only two fans. They rotate differently (for example 2520 ans 2400 rpm); maybe the one spinning faster is the one near "PS, command and control" part of the Avalon3.
For sure screw "holes" in this particular case do not improve cooling; but they're to small to do any harm anyway.

Yes, my plan also.
In Avalon3, space on top of heatsink is almost completely obstructed by hashing modules ribbons and power cables, so it's not need in there. Only between heatsinks.

That's the reverse of what pressure does. You want massive pressure inside, that's what fans are doing.


Try putting a tiny hole in your air bed, suddenly you need a pump just to maintain current pressure. Or a hole in your hose pipe. Then try 20 holes.

I disagree to a certain degree. You don't get massive pressure from fans, thats not what they do. They move air. Did you look up what pressure a "normal fan" gets you? http://www.corsair.com/de/cpu-cooling-kits/air-series-fans/air-series-sp120-high-performance-edition-high-static-pressure-120mm-fan.html this has 3.1 mm/H20 which equals to around 30 Pa. If ambient is 1 bar, this will put another 0,0003 bar on top of that (I don't use psi, but you can convert it I easily). So 0.03% increase in pressure is not what they do, they move air like i said.
No offense, just wanted to state this (correct me please if I'm wrong in someway)

Total surface of the screw holes is much less than the "hole" in the back. IMHO they're too small to do any harm or improvement.
But... have fun. Stick some tape over the holes and tell us the results.

BTW, you know how the inventions appear. All the people know that some things are impossible. From time to time, a guy who doesn't know appear :)

"Pressure ratings" you see on fans is the static pressure the fan can overcome, and isn't the pressure it generates. Its all bernouli's equation, airflow is being converted into pressure into airflow into pressure etc.

The easier way to imagine it is in watercooling. If you add a component, it creates a resistance. The pump then needs to overcome that resistance. That power to overcome is the rating you see on fans.

tldr: the pressure generated inside the case is not the same integers as the pressure rating on fans.

I did have a go but the tape I found first was shitty poundland electrical tape which wasnt sealing properly.

V2 mod to create wind tunnel. Should be no wasted air now [ignore 4th module area, have one incoming so not taped it yet].

http://img.ctrlv.in/img/520335b675e8f.jpg

did u replace the top led fan with something else? or was it part of batch 2?

anyway so how was the results for the tape mod u did? any improvements in noise or temps?

i'm getting some akasa noisemats soon.

Any significant improvements on temps/Utility?

Its a B3 but physically B2. Top fan is important to prevent back flow.

Hard to quantify the improvement as my units are almost always on lowest fan RPMs. Temps are +23 and +25 over ambient.

ok
I just did a similar mod for the Batch 1

all i did was tape the open areas between fans and the units. the units in batch 1 are very closely packed together so there's no need to tape it between the modules like dogie did.


Anyway results are rather clear from just 20mins of run time

temps stay the same but the fans work lesser to lower the temps.

they tend to stay at their max rpm for a shorter duration when it reaches the threshold temp
most of the time it's below 3000rpm  (the fans are delta afc1212de instead of the nmb ones)

I found similar results. In my setup they never have to run at max rpm anyway, so the 'idle' or maintaining rpms are lower for the same temps.

@ Dogie

If you use tape then you remove a bit of cooling surface from being effective. If you do it for alot of different holes, (bottom, top, sides, then that is a significant amount. You may cause unnecessary insulation on the aluminum surfaces.

*doesn't understand thermodynamics, post ignored*

Very cheeky,

http://img.ctrlv.in/img/520335b675e8f.jpg

Look, you covered the top of the heatsink in tape. That creates a minor hot spot inside the heatsink (along the top). Why? That would be because the tape is not allowing the top surface of the aluminum heatsink to come in contact with air. Therefore part of the heatsink will retain heat unevenly.

Don't quote thermodynamics if you didn't even notice that much. :D ::)

Simply move the three modules to the right (by one slot) and you'll get a bit better cooling across the three modules. I did it already about a month ago during my upgrade and it worked just as good as the person who figured that out before me.

The reduction in surface area is negligible compared to the now increased air flow at same fan rpms. Velocity increases >> tiny surface area decrease.

someone suggested to remove the whole back plate (with the 2 fan holes in it), he said he got 2°C better temperatures with that. Disadvantage is that you can't fix the PSU with screws then.

It would reduce 'back' pressure, and so increase the airflow for same rpm/noise further. Makes sense

ok i tried doing some more mods

this time, adding 2 more fans on the outside of the case at the back (batch 1) and removing the fan grills. original fans at the front (actually the seller changed it to a different model, not the NMB types)
added rubber grommets for the rear fans to reduce vibrations-type noise.
couldn't add grommets to the front fans as i did not have bolts and screws that are long enough and the stock self-tapping screws are not long enough.

but strangely, my unit took a longer time to heat up and when it did, the front fans didnt spin at max rpm until it was way past the threshold temps.
i set the threshold temp to 54 degC and normally by when it reaches 51 degC, the fans would spin up loudly but this time round the fans only reached max rpm when temps touched 56 degC.



Separately I also tested using placing the unit vertically and horizontally, both with a box fan blowing at the hotter side (where the heatsinks are mounted).

the unit repeatedly overheated despite placing the hotter surface facing up and the box fan blowing at it, slightly angled towards it.

when placed vertically, it performed far better, maybe because the box fan was blowing directly at the hotter surface. it was able to hash overnight and for hours on end until the aircon was switched off.


Combined test: with 2 fans at the back and unit placed vertically with box fan blowing at the hot side

Results
front fans RPM are significantly lower than before, from 3700-3800rpm to 2600-2700rpm

noise wise (measured using some app on my phone), small changes, a few db lower but at least it's not that loud and high pitched.

temps have stabilised at 51 degC, and 2600-2700rpm.



More mods planned:
adding heatsinks to the hotter side (outside of the case) and mounting fans on it.

adding rubber c-lines to each edge, where the panels meet and adding rubber grommets to all fans.

use epoxy on the casing to secure the nut to make it easier to bolt it in.

the long term plans is to design and maybe get waterblocks milled for this.

I really don't understand how people's units get so hot. Mine run at 49C with minimum fan rpms (nearly)

how cold is your room in the first place?

Ambient 22-28

well maybe not the entire civilised world is in the US, so of us have ambient temps higher than that

I'm in the UK. If your ambient is warmer than 28C consistently, you might want to consider relocating your mining.

Thought I might throw this into the modding section. Also got a few more tweaks to do and get things a little better improved.

Batch#: 2
Modules:3

PowerSupply:860w Corsair Platinimum Digital removed the one that come with it in this picture and mods done at time new pics to be uploaded as more mods been done.

Extra Cooling Setup: Custom mods done to control and force airflow and more directed.
Chip Frequency manually set:  355-370 depending on temps in room and also hw errors
More Options: Fans on constant 100% Now edited and changed and have fans at less then  20% at most times.
HashRate: 85GH/s is average; Max is 90+GH/s not fully tested this due to too many HW errors.

Avalon before pictures

https://i.imgur.com/oJhoPEih.jpg
https://i.imgur.com/8O7mJBIh.jpg
https://i.imgur.com/r6hynwGh.jpg
https://i.imgur.com/zae49Uah.jpg


Avalon after air flow mods.
As you can see in first pic using the cable to hold them in place as plenty of ribbon to use to make a little fold to hold plastic sheeting in place and where the molex connect theirs about a 0.5 to 1.5ml gap to allow to create a curve for the plastic to be molded into shape to allow to curve around and make the mod fit and old in place.
https://i.imgur.com/goFkg0ch.jpg

On this picture you will see where at the top this is still covering the gaps and also where air flows so I needed to push future to allow air flow to flow through the heat sink as I was a at first blocking this so had to gently guide it through and make marks on it where to mold curves in for cornering.
https://i.imgur.com/o9tcneZh.jpg
https://i.imgur.com/C0sX5GX.jpg
https://i.imgur.com/K8MmO9Jh.jpg

Temps before and after more or less the same but not using as much fan power and after mining 24 hours sold this is running nice and cool with oc to 84GH also fans never go above 1800 now so lot better results still doing other mods in time to it to get better air flow. This is with no extra fans added maybe get even better results with some delta fans in but their too noise
https://i.imgur.com/zueMVxRh.png

Have also taken unit upto 90GH however too many hw% errors however temps solid 50c so not doing too bad. Also added new 860w corsair digital psu working perfect never takes over 730w

Currently fan never goes above 2400rpm and after a few hours of feeq range increasing to max setting fans sit at 2200 to 2400

added even more heatsinks while getting quotes for the cnc milling of my waterblock

http://img.photobucket.com/albums/v215/tarui/20130903_184811.jpg

http://img.photobucket.com/albums/v215/tarui/20130903_184803.jpg

hope the double sided tape works because i used the same tape on the external heatsinks (mounted on the hotter side panel) and hung a lightweight 120mm fan on it and the heat caused it to lose grip.

anyway i added them to the square blocks (chokes?) because they felt extremely hot (50+ degC) for the last 3 modules.

the top module does not have air from the 2 main fans blowing over it unlike the lower modules, so the top module's pcb surface is actively cooled with just a scythe GT fan blowing air, without any heatsinks and it runs a lot cooler. so i found it strange that the