I have an Outlaw Audio 7500 Amp, and the Marantz AV 7701 prepro.
I'm using XLR cables to connect the output of the prepro to a xover, with five channels and five bass/subwoofer.
With no input, or between tracks and at times of quiet, I hear a distinct 60Hz hum coming from the 5 main speakers, none from bass.
The five are powered via the Outlaw.
I read another similar complaint on AVS forum.
I noticed the power cord on the Marantz has no ground.
All my kit gets power from a Furman AR 1220.
Any others with same problem? Solution? Root cause?
TIA - BSD