Really stupid question, but please answer.

Discussion in 'Amps and Cabs' started by Blurillaz, Dec 25, 2009.


  1. Blurillaz

    Blurillaz Member

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    I'm getting sick of replacing every tube when one goes bad, is there a way to tell exactly which one(s) has gone bad?
     
  2. Scott Auld

    Scott Auld Staff Member

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    Replace them one at a time until the amp starts working again.

    Often, but not always, the bad one glows hot red.
     
  3. rockon1

    rockon1 Member

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    Yes definately replace pre amp tubes one at a time. Take a known good 12AX7 and sub it into in the V1,then V2,PI until the offeding tube is found(if any). The power tubes are a bit trickier since they should be somewhat matched and often if one is redplating its the one next to it thats the problem! So IMO if a tubes redplated for a bit I consider it unusable anyways and possibly two tubes are bad at that point.At any rate if I have a replacement thats fairly matched I'll try it in the redplated tubes place first and watch it closely to see if its going red. If it looks ok then I know its the bad one and Im good to go. If its starts going red I shut down the amp and try the one next to it. At this point if its a 2 power tube amp Ive just replaced both power tubes- like it or not. HTH Bob
     
  4. Blurillaz

    Blurillaz Member

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    Well, I know it's a power amp tube. I suppose this time I'll just buy the whole set I need so that they are all installed at the same time and next time test like you guys suggested, thanks for the help.
     

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