Speaker Hum

try plugging all the equipment into the same wall outlet. If necessary purchase a outlet strip. Sounds like you have a ground loop. You can also try reversing the polarity of the plug.

It sounds to me like you have a ground loop. try using a cheater plug which turns the three prong power cord into 2 prong at the wall end to remove the Ground pin. you can buy one at radio shack for a couple of bucks. give that a shot and if it works, go ahead and pull the ground pin out of your power cord or continue using the cheater.you might have to experiment with the cheater on your other componets to find out exactly where the ground is comming from. if that doesnt do it some amplifiers have balanced inputs that need to be shorted usually between pin 1 and 3 (only )if RCA inputs are being used. if that is the case make sure you have the Jumper shorting pins inserted in the correct place.I would advise you to contact Adcom on that. if you dont have balanced inputs dont worry about it.

If a T.V. cable is hooked up to your system, disconnect it and see if it helps...

See this other post, it will likely help you:

http://audiogo5.iserver.net/cgi-bin/fr.pl?aamps&1002308307&read&keyw&zzspeaker%20hum