1. Jackaroe

    Jackaroe Member

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    My '66 Pro Reverb is acting up: Once it's well warmed up I get periodic drastic drop in volume with a fizzing distortion sound. I put the amp on standby for 2 seconds and the amp is back to normal for 10 or 15 minutes and then it happens again.
    Any ideas guys? If it's a bad tube, why does 2 seconds on standby correct it? (Temporarily that is) :confused: Thanks
     
  2. Blue Strat

    Blue Strat Member

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    Tubes don't generally behave intermittently.

    First thing to do is clean all tube pins and sockets. See details in the FAQ on my website under Resources. If that doesn't help report back.
     
  3. donnyjaguar

    donnyjaguar Member

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    I agree with Mike. What I have seen is what he says aggravated by temperature. When you switch to standby from run, the current in the tube drops and hence so does the idle dissipation. This causes the tube to cool a little and restore the normal operation, until of course it heats up again. It can be confusing because sometimes a tube swap will temporarily "fix" the problem. Of course, the fix is only symptomatic.
     
  4. doctorx

    doctorx Member

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    Sounds more like a bad cap than a bad tube.
     
  5. Jackaroe

    Jackaroe Member

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    Funny you should say that because I did replace the pre-amp tube I thought was the culprit and it seemed ok for a while. Thanks guys, I will clean it up tonight and caps are ok.
     

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