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Princeton reverb low end distortion

1/27/1999 10:50 AM
Princeton reverb low end distortion
Recently I picked up a SF Princeton Reverb that had a bad hum and distortion in the low frequencies. I have replaced the tubes, filter caps and all the poly signal caps. And thanks to great advice from Steve @ Angela replaced the output transformer. Amp now is quiet and mids and highs sound great - low end distortion still there. I have ruled out: tubes, OT, poly caps, filter caps and speaker. All resisters test within spec. The buzz comes on if you attack any low note, and sounds harsh metallic and mechanical almost. With volume pegged, distortion is present with the bass turned up past 0. I have not replaced any ceramic caps. Don't mind doing so, but I understand current ceramic caps are lousy,so I don't want to replace any that don't need it. Any guidance would be most appreciated.
1/27/1999 4:43 PM

It may be a speaker problem.  
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1/27/1999 4:51 PM
Don Symes

You'll do better listening to the rest of these guys, but have you looked at the soldering and mechanical connections on the pots?  
As to the ceramic caps, the thing is to go for the better dielectrics, like COG, NPO, and X7R (assuming they come in adequate voltages).  
Try to avoid Y5V and Y5U as they're not very durable or stable under heat (just proper soldering kills some of them)
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