Loud Hum

I recently bought two Brystons 7Bst's to power my Revel Salons. I also have a Bryston 1.7 and I am getting a LOUD hum from ALL speakers (I run the center and rears with a Proceed HPA 3 while I purchase other 7BST's). The Proceed did not make the HUM while I was using it to power the two Salons and center channel, but now that I am using it to power the center and surrounds it is VERY loud. My Revel B 15 ALSO has the HUM (although not so loud).

Any suggtestions?

Thank you!
Step one. If you have satellite or cable TV ,disconnect the coaxal line from your set top box and tell us if the hum goes away.
Turn off all equipment & unplug everything. (This also gives you a chance to clean/check all connections) Start over but just connect the spkrs to the 7BST's. If there's a hum, there's your problem. If not, go through the hook-up sequence one piece at a time until you locate. Make sure to turn off all gear everytime you connect/disconnect.

It's been my experience if it's not the component itself the AC is the culprit and most of the time it's the AC & not the component. If it turns out to be the AC, do a search through the archives for ways to address this. Good luck.
Thank you Driver. I will try that. I also just noticed that my lights (overhead) that have a dimmer are making a hum. I have both Brystons on a dedicated power line. I will try disconnecting everything.

Thank you Darrylhifi. I do not have satellite or cable connected.

Any other suggestions?
If anything is on the same circuit as the dimmers, it'll introduce noise & it might even backfeed into your dedicated lines if everything shares a common ground at the panel. The only true dedicated lines are completely isolated, including the ground.

When I ran sound on the club circuit, I learned early on to avoid dimmers/fluorescents like the plague, as dirty AC was the biggest detriment to good sound. Same thing holds true in your house. I also recently had an electrician check out my circuit, as I could hear a buzzing through the spkrs. that I hadn't noticed before. He tightened up the ground in the panel, as my dedicated lines share the ground with the rest of the box. Just that little bit helped eliminate the buzz & I can only hear the slightest hiss now if I put my ear right up next to the driver. If you aren't sure what to do re: tightening the ground or anything for that matter at the panel, do not attempt to, as this electrician, who also happens to be an audiophile, told me more people are electrocuted in their own homes trying to do repairs than anywhere else.
Is it dimmer hum of ground loop? Good explanation at[http://www.audioadvisor.com/store/productdetail.asp?sku=TRIBGG1&product_name=Ground%20Guard%201%20Ground%20Loop%20Eliminator] Turn off dimmed lights. Hum? Unplug cable. Hum? Ground loops (caused by the cable being grounded at a different potential from your electrical cable) can also be at your equipment. Unplug all video RCAs. If there is still hum, use 3 to 2 prong "cheater" plugs from the hardware store to remove grounds from all bu preamp. If the hum is from video you may need cheaters and cable ground isolator on video grounds.
Just a quick question about isolated circuits. If you run the ground to a point outside the AC panel, I can understand that. But, since the neutrals of the circuit have to be connected to the same common ground(neutral buss, both ground and neutral go here) buss in the panel, how are you isolating the circuit from the same noise that might ride in on the ground and keep it off the neutral?
My 7BST's have a ground loop switch on the rear panel. If your amps have this just flick the switch.
Thank you for all your responses. I have one basic question. THe hum is there even when the lights are out. Could this be caused by the dimmer even if the lights are out? Also, when I disconnect the interconnects from the pre amp the hum is gone (mostly). Could it be the cables I am using?
The B15 actually is on a "cheater" (no ground) but it still has the "Hum". I am not sure (and honestly I doubt) that the electrician that installed the dedicated power lines for the amps also used a separate ground. I will do this if it is necessary. The worst hum is coming from the proceed running the surrounds and center (this amp is not connected to a dedicated power line).
Dynasys- No, if you turn off the lights, and the hum remains, it's a ground loop problem. Good thing; you don't have to listen in the dark! You don't need a separate ground for the wiring. In my system, I had a terrible time getting rid of the hum. My Plinius pre-amp had no ground switch (internal cheater?) which helped a little. Eventually I had to put a cheater on everything but the preamp ( I plugged everything into a PSAudio plugstrip,except the power amp. I put a cheater on the plug strip. I still had the hum. I unplugged the cable. Less hum. I put a cheater on the power amp. The hum went away...) I also bought a coax ground cheater to divorce the cable from the ground (you can get the mondial magic isolator from audioadvisor.com for 100 bucks.
I had a similar problem. I solved it by installing dedicated 20 amp circuits.
You've got a lot of amplifiers drawing juice and when they don't get the juice they want, the transformer hums. Not exactly sure why -- I'm a layman when it comes to the technical side and I cannot recall the explanation I was given.
Everything in my system with a transformer, amplifiers, sub-woofer, and even
AC Conditioner was humming. But, when I installed the dedicated 20 amp circuits, all humming stopped. System is quiet as a stone.
I once had a problem with hum. It was caused by Halogen lite bulbs. I asked a few of my knowlegable friends how to get rid of the hum but nothing worked.Since it only buzzed when the lites were on, I thought why not go to regular bulbs. Presto, no more hum. My friends were impressed.
Do you have any halogens in the room or nearby?
Try putting the proceed on the same dedicated line as the Brystons. You may have a problem where the lines at the panel are not on the same phase . If the line now running power to the Brystons is on the right side of your panel and the line powering your Proceed is on the left, this could be the problem.Easy to fix yourself, just shut off the power coming into your panel and check that it is off.