why is this thing humming?

Im sorry I may have not given enough info. The hum is coming from the speakers it isnt as apparent after the music is being played at moderate levels but I dont think the hum goes away. Matt

Matt, be careful with cheater plugs I put some in and the system was dead quiet but it strangled it sonically. I have Mac 501's and they send a small hum to the speakers and it varies from IC to IC but it isn't enough to be a problem for me.

It doesn't know the words? ;)

Matt, I experienced a similar problem when I switched from a Marantz Amp to Levinson. Speakers hummed throughtout and during quiet passages, you could hear the hum come through. Very frustrating. After much searching and lifting grounds, etc. I found the hum to come from my mains! The biggest culprit was a fridge connected to the same power phase (note not circuit). Problem was solved by:
- an engineer who moved noisy circuits to other phases (I have 3 phase power supply in my home)
- installing a high current capable passive line conditioner

Try this thread also. Sounds like a ground loop hum, and the hands-down most common culprit is a coaxial cable (TV) feed comming into the same circuit. Had the same problem, and the linked discussion (as well as many other's you'll find) tell you how to lick it -- if that's what's ailing you.