A dedicated line just to my system would be great, but isn’t practical in this dwelling without tearing up a bunch of drywall. Fortunately the house was built in 2005 and has a 20-amp, 12 AWG dedicated circuit just for outlets in the listening room, and I can ensure that nothing else is plugged into them. And just yesterday I made sure that circuit was fed from the top breaker in the panel, which is supposed to have benefits as well.
So I just removed the USB outlets and things sound good, possibly better. Took one of them apart and found it contains, as you might expect, several capacitors, a small transformer, and a couple of PC boards. So far as I can tell the internal workings are not "switched on" by insertion of a USB plug. I'd post pictures but I don't know how to do it on this board.
So, who knows? A cheap tweak, anyway.
So I just removed the USB outlets and things sound good, possibly better. Took one of them apart and found it contains, as you might expect, several capacitors, a small transformer, and a couple of PC boards. So far as I can tell the internal workings are not "switched on" by insertion of a USB plug. I'd post pictures but I don't know how to do it on this board.
So, who knows? A cheap tweak, anyway.