Help my MonsterPower HTS3500 is humming

Hi, Argent. Last year, I also had a HTS3500 in my system, and it also hummed. Not so much than it was audible during normal listening, but my wife noticed it when she listened to the system at lower volumes. I eventually determined that the cause was either: the transformer in the HTS3500 hummed, or there was a ground loop problem. Given that your 3500 hums, and changes pitch and intensity when the lighting rheostat is changed, the cause is most likely a ground loop. (BTW, I also have a Bryston 4B-ST in my system.) Lighting rheostats can be a notorious problem in some systems. I don't know if you have a cable TV hookup as part of your system, but if so you should start there with a ground loop isolator (available from Radio Shack or your cable company). If none of the "normal" solutions work to get rid of the hum, you might try switching out the HTS3500 and substitute a HTS2000 (which is what I eventually did). Yes, I know you lose the nice power meter on the front, and the sequential turnon and turnoff for your components.

I have nothing else in the system. CD player, pre-amp, amp, speakers. Pure listening. The only thing else in the room is a chair. I thought the hum might be caused by plugging the amp into the wall instead of the powercenter, or perhaps both of them into the same outlet. I moved the powercenter plug to another outlet, still hums. I DO NOT want to plug the Bryston into the powercenter. Bryston owner manual says that the amp has filtering circuits in it and should not be plugged into a line conditioner or surge suppressor. Also, doesn't the HTS3500 have an extra filtering system that the HTS2000 does not? The hum is quiet, but even though I can't hear it at volume I still know it's there. I originally bought the HTS3500 for my home theater set-up, but by a round-about way I picked up two of them (long story). Anyway, I had an extra one and so I brought it over to the audio system. I've toyed with the idea of taking it out of the loop altogether and just plugging my stuff into the wall. But I know the CD player is extremely sensitive to AC garbage, as are the tubes in my CJ. Of course, the CJ just has that hair-thin zip-cord power plug hardwired from the back panel. Since I can't change out its power cord, I definitely have to plug it into some type of line conditioner. Oh well, back to shuffling things around.

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.

Argent:
Did you try disconnecting one at a time the other components from the pre to see where the problem is? This requires detaching interconnects and power cables.
Do it systematically as Liguy says seems to be a ground loop.

I guess I'm just lucky as my 3500 is dead quiet and has absolutely no effect on system sound. I have it for one reason: lightning. And it never forgets to shut off the amp, first.