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

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