[prepress]

Originally Posted by FreddieFerric

I sympathize with both of you. System hums of any type drive me utterly insane. Power supplies are often the culprit, but TT's also seem especially prone to picking up a hum from close proximity to other cables or components.

OP, did you use a ground-lift or cheater plug on your TT to see if that helped the situation?

Hadn't thought of that. I have some very good ones that I was using before. Moving the TT power supply and re-orienting the power supply's power cord has helped tremedously. I am still mystified by the fact that the hum and noise sticks to the right channel only. I did another slight re-positioning of the TT's power cord so it isn't touching anything metal, such as one of the equipment rack's pillars, and just did the same test as before: with the TT, pre and power amps on, with no LP playing, I chose the MM input and increased the volume until I could hear hum, which occurred at step 24 (worse than yesterday); then the MC input, with which I got to step 64 before hearing any hum (again, my ear was about 2 feet from the right speaker for both tests).

There are other things to try. The tonearm cable is connected to the MM input; I could move it to the MC input to see if that changes anything; I can try re-orienting the tonearm cable to ensure it's not crossing any power cords; I could try a ground lift on the TT power supply cable, as I think it has a ground blade (it's a 2-prong cord). I don't want to go crazy here, but I'd like to resolve this.