Help my MonsterPower HTS3500 is humming

I had a similar problem with my system when I added amps to a receiver, it was completely eliminated by plugging into a circuit without the dimmer. (or just replace the dimmer with a regular switch, or replace the light//move it if it has a dimmer on the light) (Halogen torchete's are famous for this type of stuff..) It seems they make a huge amount of AC noise by shedding current, this sounds like your problem.

How to sell the wife on the no dimmer deal is another issue.

You can buy a "low noise" dimmer.

You can take the dimmer out and see if the hum goes away, then you find what your next step is.
Another possible cause might be that the new room is in a different circuit in the house and something in it is putting garbage in and the dimmer just adds up to it and can be misleading as the "only" cause. Hope this helps

With the lights off (window provides plenty of light), only the pre-amp causes the hum. If I turn on the CD player there is no hum. The weird thing is that when I had the system set up in my other room there was no hum. I can't move it back, though, because that room has since been transformed in my home theater. I'm going to try and plug the amp into the HTS3500, just to see if it removes the hum. If it works, I'll be starting a new thread here to ask everyone who sells the best line conditioner--something I can plug an amplifier into.

Argent, you definately have a ground loop somewhere. I am not attacking you in any way but there is a lesson to be learned and I thank you for helping me bring my point across. Too many audiophiles feel that line conditioners are the cure all for any power problem. That could not be further from the truth. If the power going to the conditioner is suspect, the conditioner in most cases will not help. If you have a bad ground you are sunk no matter what. My point is this: Can a conditioner help? Yes, but not in all cases. Before you go out and spend alot of money on a power conditioner, understand what type of problem you have. In some cases the conditioner will even degrade the sound of your system. I have seen more problems repaired with good grounding techniques and properly wired, dedicated outlets than any conditioners. Just MHO, I could be wrong.