In Reply to: Help with strange speaker buzz/hum problem posted by maxzimum on July 31, 2009 at 12:39:25:
maxzimum,I had a ground loop hum problem in my office system a couple of years ago- which had a synthesiser, computer, and Internet involved- in my case it was the multiple grounds caused by the Internet connection- this was phone line- to the computer. I well know this is frustrating!
My logic may be faulty, but by your notes on the process of elimination, it seems to me the problem may be a mechanical fault at the internal ground connections at the preamp outputs to the power amps. This is suggested by the variation of buzz/hum when you move the IC's. You might try attaching temporarily, internally in the preamp, a set of RCA female jacks to the leads that run to the preamp output jacks, thereby bypassing the preamp's output jacks. And, just to ensure the setup- run separate temporary ground leads to the preamp chassis in case the fault is the internal ground connection of the output jacks to the chassis.
Intriguing problem. Good luck on that one!
Cheers,
Bambi B
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Follow Ups
- Clearly, space aliens are sneaking in at night and kicking your preamp output jacks! - Bambi B 08/1/0910:20:43 08/1/09 (3)
- Caution: preamp output ground may not be chassis ground! - Al Sekela 11:50:59 08/1/09 (2)
- Thank you Al ! - Bambi B 15:32:02 08/1/09 (0)
- RE: Caution: preamp output ground may not be chassis ground! - maxzimum 12:35:38 08/1/09 (0)