A Shakti Stone electromagnetic stabilizer may be a useful fix for this application (at least one for each amp)
How to get rid of transformer hum?
I have a pair of Pass X600s and an ac line with about 5% clipping of the sine wave. This gives me a large amount of transformer rattle (mechanical hum). I have built a line filter with two diodes and a couple of caps that has gotten rid of 80% of the noise but I'm looking for a inexpensive fix. My power company will not fix the power coming in unless it is clipping by more than 7%. Any suggestions?
Tommy
Tommy