Yeah I didn't care enough about that to sort out exactly what sort of hum it is...either way its pretty much unavoidable here I think, bigger issues & whatnot anyways for now
But yeah you're absolutely right.
Alright, so in response to Cliff's go-ahead-run on tearing this thing down...thats done. Quite the pretty little machine on the inside, in every badass nerdy electronic way possible.
Under the mainboard, the USB connector has 4 pins. Two of these pins are soldered together, and two of them are soldered to the board individually. It looks very deliberate so I'm assuming that the two shorted together are supposed to be that way.
I have pictures of everything but I won't post those here unless cliff or matt or someone says its all right. Unless there's an issue with those pins (I highly doubt it...there's no way that happened after the testing process and there's no way they tested & installed firmware on this thing if its not correct) then I think this effectively eliminates the ax8 as the cause of my problems. Its what I expected, but I was honestly hoping for an easy 'pull that off of there' fix :/ Tomorrow I'm going to carry it to work with me, I have access to some hefty UPS systems where I can power it isolated from grid over here and see what that does.
edit: She's all back together again, no change in status. I didn't break it, but also didn't fix it
Side note, the most nerve-wracking part of that for me was tightening the plastic nuts on the input/outputs, hah... I think I overtightened them a bit.