Thanks for the response. Personally, I would send it back to Monster for repair of the hum. But if you don't want to. your best bet is individual dedicated power lines as I suggested. I also have a Signature Monster unit (got a great deal I couldn't pass up), but no amps are plugged into it. Only, pre-amp, tuner, turn table, Martin Logan Monolith IIIX speakers, phono stage, music server and two dacs. The monster has no hum and has it's own dedicated line to the service panel. I have two Audio Research VTM 120 Mono amps and a Mark Levinson ML3 with their own dedicated lines back to the panel.
I have no hum or ground loops whatsoever and sounds wonderful.
Enjoy