That is odd. The kind of interference he is describing is much like the electronic noise that you can hear on pretty much every motherboard analog 1/8" jacks. Suprising to hear that it is coming through the audio interface though. If it's a ground loop, I suppose the electronics are modulating it somehow.
As for PSU's, if you want to know which are the good ones, the gold standard
PSU reviewer is Tom's Hardware. Amazing depth into which they probe the PSUs.
There is this guide in their forums which talk about which brands are decent and which to avoid. It has this to say about Microcenter's house brand, Powerspec: "
The Powerspec units sold by Microcenter are a mixed bag. Some of them are fairly decent using the same platform as the Sirfa High power Astro lite platform, so not total dumpster fire type units, but not particularly good either, and some of their units are simply garbage and should be listed below in the DO NOT USE category, but I'm leaving them out because there are really no reviews of them and since there are a few units from them that are ok-ish, I'm giving them a "use at your own discretion but buy a better model if you can" grade.
Even a gray label Corsair VS unit would probably be an upgrade from one of those Powerspec models, and a CXm or 2017 CX would, almost certainly would, without any doubt. "