Buzz/hum from amps, NOT from speakers

Sunfire Manual Says -> "Internal hum can be made
worse by a shelf or cabinet resonating"

This is exactly the problem I had with my CJ amp. I could hear it across the room and using a cheater plug made very little difference.

The noise was actually due to a mechanical resonance in the amp case. I was able to queit the amp by loosening the middle screws on the cover and leaving just the corner screws tight (don't know if this is possible on your amp). This changed the machanical resonance of the amp case and resolved the vibration and hence the noise. This was recommend by another Agon member on a thread (since removed) about amp hums.

Eliminating the machanical resonances also reduces the electronic distortion that can be heard through the speakers. I can now use may amp without a cheater plug which of course is best.

I'm up in the Seattle area. After the wind storm and major power outages, I have buzzing in all my components, mainly the amp. I actually watched the line crew change out the toasted transformer on the pole. They ran new lines for an 1/8 of a mile. Voltage at the house has been 117 to 118. Some days it jumps up to 125v. I did have everything unplugged during the storm so I know it's not storm damamge to the equipment. I would probably contact the power company and let them know almost all your appliances are buzzing.

I have the same thing. Sometimes the buzz in all components get somewhat loud, then it slopes down to be totally quite. It then starts the swoop again and gets louder to then go quite again. Sometimes the buzz comes on and stays on when components are on.

Anyone deal with that? That must be a power issue????

Hi everyone, thanks for the replies! Here's an update, and some answers to your questions:

Nsgarch: I agree, I believe it's dirty power. A voltage check shows 119-122VAC, so it's not due to low voltage. I'm hoping to avoid buying a regenerator, as those are very expensive, and if they need to handle high current (power amps), they're even more expensive. And I have multiple amps! :-( Thanks for the tip on the Exactpower, btw. I hadn't seen that unit before.

Tarsando: No, the old equipment buzzed too, but each item has the problem to a different degree. Some are worse than others. Bad news is, I used to be an electrician, lol... I've already checked for the obvious stuff. ;-)

Restock: I already tried what you describe - shutting off all circuits except the one feeding the system. Same problem. I too was hoping it was something in the house causing it, which I could replace or remove. I may need to contact the power company. :-(

Jameswei: I agree. See above comment.

Dbtrucks: I don't have cable TV, just a DVD video source. No coax of any kind connected to the system. (yeah, I'm weird, lol...)

Joefama: First noticed it with the Polk SRT powered sub amps. They were the first item it was loud enough to hear from across a quiet room. When I upgraded from Adcom to Sunfire pre/pro, it got worse, probably due to the larger internal transformers in the Sunfire stuff. The latest is the plasma which I just bought last month (although that mostly buzzes when turned on.)

Adasilva: In my case, the cheater plug made zero difference. I'm hoping to find a better solution than physically opening up the equipment and damping the offending component (see update below).

Freemand: See update below.

UPDATE: I found a product by PS Audio that claims to cure this exact problem. It's not cheap, however. And the original product is no longer manufactured or sold. The new, replacement product is 2/3 more expensive ($499 vs the original $299, MSRP). Click links below for details. I couldn't locate the old product anywhere, but I found a place that sells the new one for about 25% off list price. I ordered one, it will arrive today, I should know if it works by tomorrow. I'll post my findings here. If this unit doesn't fix it, I will definitely call the power company next. A regeneration unit is the last resort due to the excessive cost ($1-3k).

PS Audio Humbuster (was $299, but no longer available):
http://www.psaudio.com/products/humbustermoreinfo.asp

PS Audio UPC-200HB with Humbuster circuitry ($499 MSRP):
http://www.psaudio.com/products/upchb.asp

PS Audio Premier power regenerator ($2195 MSRP):
http://www.psaudio.com/products/premier_power_plant.asp

Bad news: The UPC-200HB didn't cure the problem. I think it may have reduced it, but not $400 worth. I sent an email to the power company already.

Anyone want to buy a new-in-box UPC-200HB? Drop me an email...

:-/