Getting a very loud hum from subwoofer. EP 500 connected to a Denon 3808CI. I am guessing its a ground loop, and wondering the best suggestion for a fix.....thanks

is the subwoofer plugged into an outlet on the same AC circuit as the other components? It also can be a result of other equipment in the mix, for ex., direct tv receiver.

I haven't hooked up cable or satellite yet. I may try the extension cord route, try a different outlet. Almost wondered if it could be Rogers internet running through Boxee. I was just doing a little reading and could be the amp and the sub fighting for 0.00 volts.

is there a hum when just plugged into outlet, and no coax, or just when you introduce the line in coax?

with coax, and the hum stops and starts when switching inputs/signals on the receiver, say from Boxee to PS3.

My 600 did that as well, and I removed the gound screw on the back, which was an option back in the V2 series, not sure the 500 has that on that back, hmmm. If you unhook other equipment from receiver, and add them back one by one, I wonder if one of those items is causing the issue. Possibly the HDMI on the Ps3. Ground Hums suck.

I tried pulling all the inputs, still no luck. I'm going to guess that a new/better power bar won't do the trick. hard to find a separate circuit in the same room.

If there's nothing hooked up to the sub except power and it still hums, it's not a ground loop. Call Axiom.

it only hums hooked up to coax going to the amp.

See if you can ground the Rogers to the main house or other available ground. I had the same issue from Rogers and solved it by grounding my main Rogers coax coming into the house at the demarcation point.