Quote from: Deeped on July 11, 2019, 01:39:29 AM

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!

If you are serious about going with asics, you have to switch that voltage. With 120v you are going to face many issues and spend a lot of more money.
An asic miner that would normally take like 8a on 240v would pulling above 16a on 12v, beyond the 80% safety marging (your 20a circuits won't do).

And you are going to spend a fortune in PSUs, and risk additional problems if you use dual psus or such per miner.

Only solution i could see for this if you are stubborn with voltage, is don't use full miners. Perhaps just use one or two boards per S9, and with BraiinsOS make it run as efficient low power as possible, to consume the least amount of power per hash which might be accommodated with a single psu per unit. And they would also be more quiet, but of course take more space (you'd need more cases).

Yes, at some point ago they implemented KYC procedures.

You probably won't ROI them that quick unless the price suddenly spikes, maybe plan for 1 year or more to be on the safe side. Also the asic manufacturers are a bit slow too, it also depends on market demand and bitcoin price. GPUs are more flexible there.