Hi everyone - I am thinking of shutting down a sizable GPU farm and switching everything over to ASIC.  Only issue is, while power is free, it can only be 120V wiring, no way to change that.  Breakers are 20 amps, with a couple 15 amps.

So I think any S9 will be ideal?  Whereas the more recent ones can only be 220 volts due to power supply being integrated with the unit.

Other unit I am considering is Z11, because judging from specs, I think it will do ok 120 volt 15 amps (and certainly on 20 amp breaker).

I was ready to start buying used S9s from Alibaba, but now that I see the new ones are only $350 with PSU direct from Bitmain, I guess it's better to just keep running things as they are until the next Bitmain order?

Also I am hesitant about Zcash (Z11), as not only is difficulty there going up rapidly, but price is also going down against BTC.  With BTC current activity, I am pretty sure we'll be seeing new highs by end of year.  I want to be aligned with that by having all machines that generate BTC directly, ideally.  Best I can do now is point machines at NiceHash instead of mining alts directly.

Thank you anyone for any thoughts, buying advice, etc.  I guess the downside with ASICs is still the same two years later - one has to plan on replacing all machines at LEAST once a year to stay relevant?  And ideally every 6 months, or every 3 months, and sell the old gear ASAP.  So, maybe not worth it at all if I don't want to be constantly trading up like that.

Also I don't know if anything has changed with Bitmain buying recently?  I saw they now require ID upload - says passport but I used driver's license, I assume that works.  I know one has to be "ready" to buy when the window for ordering opens up!

Hello,

I am trying to figure out which miner is best.  I have 120 amps in total of 120V power I can use.  The newer S15 and S17 have built-in power so they cannot be configured to use 2x 120V power supplies, right?  So I think I am limited to the older S9, and even then might need to underclock a bit.  I do not have option of changing power, it's fixed.  (but also low rate)

The safest bet would be to buy the old S7 because they're cheap and on Amazon/eBay, and would recoup their cost in a month, but never would earn much.  (power supply would cost more than the machine).

Other thing I considered is Z11, that SEEMS to be ok at 1400 watts on a 20 amp breaker?  But very hard to find a reliable source to buy.  For example, the newest one is the 135ksol, but those are not out yet, are they?  I've contacted this company twice and they swear they have them in stock:

https://genimining.com/product/bitmain-antminer-z11-135ksol-s-zcash-miner-brand-new/

But I cannot find any mention of their site on this forum.  On the other hand, people vouch for that lakeshore xyz one all the time, and they don't have much in stock - either pre order for z11 or hydro S9.  But at least they show mostly out of stock, whereas this genimining.com has EVERYTHING in stock.  (But site looks well done otherwise, even better than the xyz site.)

Anyway maybe pre-ordering Z11 is better?  But, i don't want to get stuck in a "space race" ASIC.  Equihash miners have doubled their output a few times so far!  Whereas SHA-256 miners have leveled out a bit more.  Yes, the new S17 is almost four times the latest S9, but it uses a bit more power too, and costs a lot more.

Any other things I should look at?  Trying to get out of the GPU game, these things will never ROI and I fear there will be no more good GPU coins soon.