Loud Hum

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?

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).