This is a first post. I hope someone has run into this before and found the solution.
I am running a pair of BC REF1000's with an Antique Sound Labs pre and have a dreaded ground loop. It is definitely a 60Hz hum and related to the AC coming into the amps. When I shut them down they will play music without hum for 2 or 3 seconds if the source is on.
I have tried changing the plug in location and even changed the preamp out with no effect. If I hook the amps up directly to a source this problem goes away. Thoughts?