re: still trying to track down a hum...

Posted by FenderLover on September 17, 2012 at 06:41:24

In Reply to: re: still trying to track down a hum... posted by mr9iron on September 15, 2012 at 01:41:53:

I feel for you. Hum is the bane of all fixer-uppers & DIY'er. Have you checked the resistance and grounding of the grid-to-ground resistors between the input and the input tube?

Specifically, the 1meg-ohm (gtg) and 10k-ohm grid resistor. I hope that I have the correct schemo. Use the best resistors for these points. It's worth the extra $$$, in my opinion. Esp for long, quiet, reliable life.

All ground points MUST have as close to zero DC resistance between wire and chassis. You may want to make a brass or copper raised bar to solder all input points (maybe even insulating the jacks from the chassis with teflon spacers). Then have a single grounding point, for the brass/copper buss. I'd put it as close to the main PS filter ground pointing as possible.

I'm sure Jim McShane has a ton of better ideas about this issue. May want to email him.

Good luck. Sorry, no magic bullet for this one.

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Follow Ups Full Thread

Topic - re: still trying to track down a hum... - mr9iron 01:41:53 09/15/12 (16)

re: still trying to track down a hum... - Ron V 03:43:27 09/21/12 (1)

re: still trying to track down a hum... - mr9iron 14:18:17 09/21/12 (0)

re: still trying to track down a hum... - DannyR 12:10:52 09/19/12 (0)

re: still trying to track down a hum... - FenderLover 06:41:24 09/17/12 (1)

re: still trying to track down a hum... - mr9iron 10:45:20 09/17/12 (0)

re: still trying to track down a hum... - Tre' 07:07:06 09/15/12 (10)

re: still trying to track down a hum... - mr9iron 10:11:35 09/15/12 (9)

re: still trying to track down a hum... - mr9iron 02:05:33 09/16/12 (3)

re: still trying to track down a hum... - Tre' 13:46:52 09/18/12 (2)

re: still trying to track down a hum... - mr9iron 14:08:34 09/18/12 (1)

re: still trying to track down a hum... - Tre' 11:01:54 09/19/12 (0)

re: still trying to track down a hum... - Tre' 17:28:03 09/15/12 (2)

re: still trying to track down a hum... - mr9iron 20:19:30 09/15/12 (1)

re: still trying to track down a hum... - Tre' 07:37:29 09/16/12 (0)

Classic ground loop - Chris O 11:14:37 09/15/12 (1)

RE: Classic ground loop - mr9iron 20:25:51 09/15/12 (0)

Follow Ups

re: still trying to track down a hum... - FenderLover 06:41:24 09/17/12 (1)

re: still trying to track down a hum... - mr9iron 10:45:20 09/17/12 (0)

re: still trying to track down a hum...

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