Has this ever happened to you??

Discussion in 'Amps and Cabs' started by ala02c, Jul 16, 2008.

  1. ala02c

    ala02c Member

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    Old Classic 30...I was practicing on it today (Vol. at noon normal chan.) hit a chord real hard and sound dropped out. Signal comes through but was very faint, and distorted. Turned off and then on again, worked normally for a bit then same situation. Seems like a tube issue? Any ideas are appreciated...
     
  2. rockon1

    rockon1 Member

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    Could be a tube issue. Could also be an FX loop jack issue if the problem occured when it wasnt being used. The contacts in the jacks get dirty and sometimes drop out the signal. Try putting a patch cord or guitar cable in the loop to bypass them if this is the case. Bob
     
  3. StompBoxBlues

    StompBoxBlues Member

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    I think it could be a few things. Tubes (but I doubt all the power tubes are going bad at the same time so....)...

    what happens when it starts happening if you don't turn it off...it stays that way? If it is hot/warmed up does it happen again faster next time?

    I would (hope) change out the preamp tubes...or change them around anyway, and see if it helped. It could be the power supply, or the supply caps I think.

    Try tubes first.
     
  4. ala02c

    ala02c Member

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    yes if it is turned off then on again the problem happens faster. yes if i keep playing it stays that way.

    one thing i was able to try last night was switching V1 and V2...same problem happened, in exactly the same way as before.

    thanks for the replies, i will try switching preamp tubes one by one (with good 12ax7's) later today and report back.
     
  5. DavidG

    DavidG Member

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    Sounds like a problem I had with a classic 50 once. I took it in to peavy and it turned out to be a transformer+tubes. Not saying that's your problem by any means.
     
  6. mmorse

    mmorse Member

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    Just had the same problem with my Marshall. Turns out it was a loose input jack. Tightened it up and problem solved.
     
  7. 5E3

    5E3 Member

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    Yes, it happened to me and was a failing power tube.

    IMO, Tubes are definitely first thing to check. With the amp on see if any of the tubes are red-plating. Then try swapping in replacement tubes if you have them, or changing positions of the current tubes (same type in same socket of course: pre-amp->pre-amp, power->power). If it's not the tubes it may be a loose jack as others have indicated.
     
  8. rockon1

    rockon1 Member

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    Dont dismiss the FX loop in case the tubes are ok. Bob
     

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