Lowering the noise floor


Active member
I have an E580. I recently swapped out the tubes (JJ 12ax7) for some Ruby's with a TungSol in V1, and the noise floor increased noticably when the hi gain mode is engaged. Backing off the guitar volume about 20% helps. I tried two different TungSols. The reason I swapped the tubes was to try to lower the noise floor in the first place.

Curious if anyone knows which tube besides the V1 influences the hi gain path? Any ideas besides trying a 5751 or 12at7? I saw there are low gain graded Tung Sols, but not sure if the V1 is the only problem?

And since I know this a less common amp, I'd be fine with input from 570, 530, Savage, or Blackmore users, as I think the preamp sections are similar enough.
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