Tube Amp overheating. Help?

Discussion in 'Amps and Cabs' started by therealme, Jul 23, 2008.

  1. therealme

    therealme Member

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    My Fender Quad Reverb has been getting extremely hot as of late, to the point where the speaker cable is almost too hot to touch.

    There haven't been changes in the way the amp sounds, and I don't think any tubes are blown (but I could be wrong about that).

    Any thoughts on what the problem might be?
     
  2. shngn7

    shngn7 Member

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    If you leave a tube amp on for long enough the tubes will get really hot and with poor ventilation could make the whole interior feel very hot. Whenever I use the tilt back legs on my Super Reverb I make sure I put a small fan behind it about 5 feet away just to circulate the air insie. You might also want to check your bias. If your tubes are glowing red hot that's a bad sign and you should unplug your amp. Try the fan if you don't suspect any serious problems with your tubes.
     
  3. SkipTracer

    SkipTracer Member

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    I'd take it to an amp tech.
    Sounds like the power section is running too hot, for whatever reason. Since this has only occured "as of late", something must have happened inside there, so a fan / better ventilation won't be the cure.
     
  4. BudLite

    BudLite Supporting Member

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    Have you checked the amp bias? Also check all your tubes...or bring it to a amp tech to inspect....The fan will just blow dirt into the amp....
     
  5. Blue Strat

    Blue Strat Member

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    +1000. Assuming that the amp is in fact getting hotter and you're not imagining it, the power tube bias is probably drifting and/or way off.

    Could be a power tube, socket, bias circuit, etc. If the amp hasn't had a "cap job" it's about 20 years overdue. A shorted or leaky (electrically, not visibly) bias cap is often the cause of bias problems in vintage amps.

    The amp likely needs a tuneup. At very least you should check the power tube bias with a bias probe.
     

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