Ground Loop Hum

try floating the ground with a 3>2 converter on the AC. Or to quote Mary Cardas build a new house.:-)

Rick

Subwoofers often generate ground/hum loops.
To fix it, only one component in your system should be grounded through the AC cable. The remaining ones should float through 3 prong to 2 AC adapters, otherwise there will be a ground loop.
For safety reasons, I suggest that you ground the BAT amplifier through the AC cable, it is your component that draws the most current.

Also, disconnect the ground wire between subwoofer and preamp, it forms a ground loop, because the ICs carry signal ground from one component to the next.

Also: if your amp is a bridged design, the speaker (-) lead is floating and should be left floating. DO NOT ground the subwoofer high level (-) input.
I hope this helps

unplug your cable box from you system to see if it goes away. If yes, its a ground loop the cable box has created. visit axiom speakers website and get a ground isolator make sure its wide bandwidth if you have a HD cable box. you may also try the line level ground isolator Radio Shack offers.

oh, DO NOT FLOAT THE GROUND. NEVER! If an electronic is designed with a power cord thats 3 prongs with the ground, it is because by code it required so. FLOATING THE GROUND IS UNSAFE! I wonder what the insurance company will say if something happens to your house if the malfunctioning unit catch on fire or something ... DON'T USE THE CHEATER PLUG TO FLOAT THE GROUND IF YOUR UNIT HAS A 3 PRONGS POWER CABLE!