Do you get the same hum when operating another piece of equipment like a transport? If so, it may be your processor. I had the same problem and it turned out to be a grounding issue. I had to plug the left channel mono amp into a three to two plug converter, then into the dedicated PS Audio receptacle. Problem solved. Just food for thought. If I switched IC cables the hum came through the other channel so it became obvious that the problem was with the processor, not the transport or mono amp. At least that was my experience. Maybe it is helpful.
Loud hum in one channel
I just finished setting up an Empire 598 III turntable, and, unfortunately, am getting a fairly loud hum out of the left channel, which will happen on the right when I switch the leads. I am using a Sumiko Blue Point, and the ground wire is connected. Any help on solving this would be greatly appreciated!