Yup ... the Carver did have some issues with AC noise in the signal path. They also cut a couple corners when it came to bypassing a couple of the ICs, and I don't suppose I helped any by replacing some of those with current tech Burr Browns. Even considered running 0.1 AND .01 caps parallel wherever I added a bypass to catch a broader noise band, but that was just a passing thought. Best I can say is the mods made for some significant improvements in the imaging and overall SQ.
Only hum I get is a bit of mechanical vibration from the PT. Once again, not so you'd notice unless you're right on top of it. Nothing going thru to the speakers - with all the wire re-routes and mods, I figure I got dumb lucky there. I did use the rubber washers between the iron and chassis, but may have gotten the holes a bit tight, so there could be some thread contact. Long as I'm in there, I'll add rubber washers below the board, and maybe add a dab of black silicone to help isolate the mounting screws. May help, may not ... no biggie if it doesn't.
Even with that, the ST120 is quieter than my McIntosh MC2205, but that's like ... 35 years old? And the Big Mac ain't no slouch when it comes to "black" either, so either way, I'm a happy camper.
Or will be once I figure out the meter thing ... I'll be bangin' away on that later today and keep my fingers crossed.