Guest HRB853370 Posted April 15, 2011 Share Posted April 15, 2011 This just started, and I am clueless. It seems to calm down a bit when the amp reaches full operating temp with a Heritage plugged into it. But with new tubes (August) it should not do this. Should I check that they are all seated properly first? Any other quick and dirty diagnostics? Link to comment Share on other sites More sharing options...
Hfan Posted April 16, 2011 Share Posted April 16, 2011 This just started, and I am clueless. It seems to calm down a bit when the amp reaches full operating temp with a Heritage plugged into it. But with new tubes (August) it should not do this. Should I check that they are all seated properly first? Any other quick and dirty diagnostics? Is that a Peavy Classic 30? Does the hum occur if you have no guitar plugged in? If not it is not the amp. Have you tried a different outlet. Nothing else around that could be generating noise? Flouresent lights etc. Not sure what tubes you have in the amp. No harm in reseating them (with power off, pull partially out , careful might be hot, and push back in). If still occurring, you could try (if you have several tubes of same type like 12ax7's or spares) switching positions of the pre amp tubes. I would mark them with a sharpie so you know where you started. Link to comment Share on other sites More sharing options...
smurph1 Posted April 16, 2011 Share Posted April 16, 2011 Had the same problem with my Classic 30 a couple weeks ago before a gig..Switched a couple of pre-amp (small) tubes, and it went away..Good Luck Link to comment Share on other sites More sharing options...
blackjack Posted April 16, 2011 Share Posted April 16, 2011 A microphonic tube is the first thing to check. I had one last week that as soon as it came out of standby would start an odd oscillating noise that sounded like a cat in heat. The amp was not "possessed", it turned out to be the phase splitter. Sadly, it was an NOS Admiral branded tube that had 4000 hours on it. If swapping out one tube at a time doesn't find a bad tube, then it could be a loose or bent connection in the socket. Link to comment Share on other sites More sharing options...
Guest HRB853370 Posted April 17, 2011 Share Posted April 17, 2011 Is that a Peavy Classic 30? Does the hum occur if you have no guitar plugged in? If not it is not the amp. Have you tried a different outlet. Nothing else around that could be generating noise? Flouresent lights etc. Not sure what tubes you have in the amp. No harm in reseating them (with power off, pull partially out , careful might be hot, and push back in). If still occurring, you could try (if you have several tubes of same type like 12ax7's or spares) switching positions of the pre amp tubes. I would mark them with a sharpie so you know where you started. Yes, PV C30. Hum is there guitar in or guitar out of input. I will try the seating remedy. Tubes were new JJ in August. Perhaps one already is going bad. Thanks. Link to comment Share on other sites More sharing options...
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