CryptoTab is a SCAM! Period.
Since at least 2013 it has been impossible to mine BTC with a PC much less a smartphone. Odds are it will be loaded with malware to try and get hold of your accounts. The very few (if any exist) clean variants out there that are not scams mine XMR (Monero) or other very low difficulty altcoin which (if it pays out at all) is then eventually paid out in BTC. You are talking about a few pennies per-day at best. Just do a search for it with your fav search engine for details...

You are comparing apples (BTC) to oranges (alts) and discussion of that belongs in the general Bitcoin Discussion area - not here (BTC only).

You are obviously very young and have little historical knowledge of the Financial world....
Try taking a look at the 1980's and the financial shenanigans that occurred on Wall St and other sectors of the economy. Remember Junk Bonds? They were very similar to the ICO/Tokens crapcoins of today and just as risky (largely worthless). Going further back you will find that throughout all history the same shit has been happening.

In short: Nothing new. Different day, different way, but still just greedy people doing what they do.

Not correct. Kwh is total power over time. The newer ASIC's constantly consume over 3kw at any given point in time and that works out to over 72kwh per 24-hour day.

What faults? All of my several dozen 841's have been bulletproof - as in zero failures over the years -  and are exceptionally tweakable. Their only fault is their efficiency is not the best.

I have 2 of the A1041's and 5 of the 1047's, zero PSU failures... Where are you running these to have so many issues?

My guess is that cgminer is one of the payloads that many malwares carry so virus checkers just automatically black flag it w/o bothering to check if a real virus is present to make use of it...

If you mean the 'one Vcore for all' boards, I've mentioned that several several time in the past. Using the PSU to do all regulation saves several % eff vs each board having final on-board Vcore regulators and is a large part of the higher power eff of modern miners.

I assume what is happening is that like Canaan does the software is slightly tweaking the the speed per-chip based on tracking some majik error-rate parameter. Canaan likened it to fiddling with a radio receiver s/n ratio

That is very wrong. Line voltage only affects current on the AC line side of a PSU and has zero effect on the output (as long as the line is high enough for the PSU to work that is...). All the rest is 100% correct.

Given the age of the gear I lean to the PCIe connectors being loose/worn out. As I've said many times before, those connectors have a very short mating cycle lifetime. The highest quality ones are only good for around 25 plugging/unplugging cycles before the pins are damaged. El-cheapo ones, well....

Interesting problem. I thought there was legislation in motion to alleviate the Cannabis income banking quandary in the US. I take it there has been no motion on the SAFE Banking Act?

Cloud mining is almost ALWAYS a scam. Do NOT use it - period.
That said, you need to read the pinned topic at the top of this area. Cloud mining and all altcoins have their own areas found under here. This area is only for mining Bitcoin using ASIC-based hardware.

To paraphrase what Davis196 said above, who the f**k cares and why? Morbid curiosity?
The dude was a 1st class jerk who bankrupted himself and on the way down took a lot of investors with him.

It would greatly help if you told where you are located as that makes one helluva difference...
If you are in USA the I'd recommend using Blokforge.com who does have stock of Canaan miners. They also happen to be an Authorized distributor for Canaan.

So what if Bitmain does cut back on spot-market sales of new gear? Safe bet that Canaan, Innosilicon, and MicroBt won't and will be quite happy with their increased sales of new gear. Temporarily halting spot-market sales (read as: individual or very small volume sales) does not mean they will slow down on large-volume sales to mega farms in other parts of the globe. In my book it is a win-win all around for buyers and other miner manufacturers.

Source?
Nothing about it on the official Bitmain news site.

Also one must note that the ban on mining does NOT include a ban on making miners. Bitmain, Canaan et al are still free to keep on making the hardware for sale to the rest of the world. The hardware just cannot be sold for use in China.

 As for the large mining farms which were mostly based in China, they just have to move the hardware end of operations out of the country. As I said earlier, they also will now have to use exchanges and banks that are based in other countries to reap their rewards.

Yes, that *was* the 1st answer. The 2nd is that the people creating and running the mining operations in China are <drum roll please> Chinese, which of course made it a natural choice to base their operations there.

Up until recent events, China had been more or less rather friendly towards crypto mining. The crackdowns in earlier years were all aimed at getting rid of scammers involved in the rampant flood of ICO/Token crapcoin pump & dump schemes.

As far as miners go, all of Bitmain, Canaan, and MicroBt's gear *are* UL listed/CE certified. That said, at least for CE certification all that means is that the components are properly rated and the design is not likely to catastrophically fail resulting in a fire or electrocution hazard. UL takes that a bit further in that the assembly factories must also allow periodic 3rd party audits to ensure all guidelines are followed. The fact that whoever makes the PSU's seem to *really* like using glue to insulate and hold parts in place is permitted although certainly not consider a best-practice.

Globally, transformers with aluminum windings are the norm when it comes to large ones used for power distribution and ones using copper are rather rare to find...

Now as to the switchgear, ja they need to check certifications but odds are it is all at least CE Certified.

The hell with Iran. To me a better choice would be moving the miners to Kazakhstan which not only has ample power but is also extremely friendly towards crypto.

The farms being ran for BTC.com is already moving there

Why would the owners be arrested or detained?
Nothing anywhere has been said regarding that and there is no legal basis for such speculation. As long as they follow the new law(s), shut down and/or move operations out of the country they will be fine.

Yes they will have to deal with setting up accounts with foreign exchanges and banks to receive their mining earnings through and then sent/receive Yuan to their Chinese accounts. That is not only fully legal but also a very common practice in international banking. Again, as long as business owners follow the rules -- no problem.

Yes, either that or a final rinse with IPA (isopropyl alchol). As said earlier, tap water usually contains minerals and salts along with whatever was used in the detergent you use. The final rinse removes the remaining residue.