tube guitar amp help

Discussion in 'Miscellaneous [BG]' started by StoutXXX, Jan 21, 2004.

  1. If this would get more responses in amps feel free to switch it. I jsut didnt know if a guitar amp was kosher there or not. Anyway. Crate blue voodoo 4 6l6 and 4 12ax7 tubes. Started feeding back something fierce and gets worse . Thought it was a ground in the guitar . Fixed that. Sounds microphonic to. But doenst feed back onc lean channel. Should we just switch preamp tubes for new ones? suggestions?
  2. Trevorus


    Oct 18, 2002
    Urbana, IL
    do the flick test. Turn the amp on, plug in just like you are going to play. Then give the preamp tubes (one by one) a tiny flick of the finger. Be gentle. The one that makes the funky noise is the culprit. try that. Usually that's preamp tube. Good luck, buddy
  3. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    Could be a bad cathode cap.

    How old is the amp?

    Does it happen with and without the reverb on?
  4. uner 2 years but man it gets run full blast everday. master at like 7 and pre all the way. It has been a road and gigging amp to.
  5. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    Well, if it's only a couple years old then a microphonic tube is much more likely. Good tubes are pretty cheap again (thankfully), you can JJ 12ax7's for about 7 bucks each (check eBay), and a factory matched pair of 6L6's for about 30 bucks. You can retube your entire amp for under a hundred. If you get the JJ 12ax7's (actually they're called ecc83s, which is the European designation), make sure to get the new ones, preferably made this year, they're a lot quieter and they sound a lot better than the old ones from several years ago.
  6. Well It sounds better with sovtek lps tubes for the preamp but still kills with feedback witht he pre and master cranked even without playing? any suggestions? noise gate? Power tubes?
  7. aaahhhh a capacitor....