I biamp my rig, and with two different amps for the bottom end I get a ground loop effect. With my recently-installed Forte Mdl 3 amp in the bottom end the buzz was different, barely noticeable, so I ignored it.
When I plugged the system back in tonight after some storms I threw a cheater plug on the Forte. Buzz is all but gone and the low end is much better! Give it a try!
On my Parasound 1000 the hum was worse, but also disappeared when I ripped out the ground post on the plug.