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Buzz/hum from amps, NOT from speakers

I have been tearing my hair out over over a buzzing noise coming from almost every component in my system. I have it in all three subwoofers, the power amp, preamp, and - the latest addition - my new HP plasma TV. All will "buzz" quietly as soon as they are plugged in.

Using a power console makes no difference, and I've tried both a Monster Power 3500 MK2 as well as a Belkin PureAV PF-60 (both are ~$500 units). I've tried the ground-plug "lifters" that turn a 3-prong AC plug into a 2-prong, same problem, no change. Removing the audio interconnects makes ZERO difference. The noise is present with ONLY the AC cords attached. I tried shutting off EVERY breaker in the panel box except the one that feeds my system, no change. I have tried different circuits, no change.

Sunfire mentions this in the owner's manual, which sounds like what I'm dealing with, but they offer no solution:

"If the hum is heard from within the
TGIV and not through the speakers,
this may also be caused by
interference on the AC or DC lines.
The power transformers may turn
this interference into an audible
noise. Internal hum can be made
worse by a shelf or cabinet resonating,
so try moving the TGIV to another shelf."

Equipment affected:
====================
Sunfire TG IV preamp
Sunfire Signature power amp
Sunfire Signature subwoofer
Polk SRT main powered subs (L&R)
HP PL5060N plasma TV

HELP!!!!

:-(
gsxr
nsgarch's avatar
nsgarch
2,524 posts
 
You mean the equipment itself is physically buzzing/vibrating? Sounds to me like you're getting lousy power from the utility company -- probably low power (well under under 120 V, like 100V) and maybe off-cycle. Check your power at the wall outlet using a simple volt-ohm meter. You may wind up needing a power regenerator like an Exactpower EP-15A (conditioners won't do anything to fix this problem).
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tarsando
578 posts
 
Is this the first equipment you've used at this location??? If not, did your old stuff buzz too? If no old stuff, maybe buy a $29.95 boombox and see if it hums. And then call an electrician would be my take on it.
restock
831 posts
 
Most likely you have a strong 120 Hz noise riding on your lines. One hint: I had a similar problem on one of my amps: The problem was caused by a dimmer that caused the transformers to buzz at 120 Hz.

A good way to diagnose the offender: Shut off all lines in your place at the switching panel and leave only the line to your system running. If the hum disappears keep adding line by line and see which one and if possible which appliance on that line causes the problem. If it doesn't disappear I would talk to the your electricity supplier.

Good luck!

Rene
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