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SVT 2 Pro problem

Discussion in 'Amps [BG]' started by Altarsmadness91, Jan 3, 2014.

  1. Altarsmadness91

    Altarsmadness91

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    Hello, I've been having a pretty serious problem with my SVT-2 Pro and I'd be very thankful if someone could give me some advice as to what's going on with it.
    Anyway, I'll let it warm up and then turn it on and start playing and everything sounds fine for only about a minute and then bam, everything disappears! Volume is slim to none, even with the master at full :eyebrow:
    The most volume I can get out of it after this "drop" is about the volume of normal talking. And every time I shut it off after this, it pops with the meanest pop I've ever heard come from an amp.
    I'm not a smart guy when it comes to tube amps, not sure if this is Power tube or Preamp tube related but if anyone would know anything about this symptom, I'd greatly appreciate it, Thank you! -Andrew
  2. B-string

    B-string Supporting Member

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    Best over the internet can't see your amp from here guess is a bad (small) driver or PI tube.
  3. JimmyM

    JimmyM Supporting Member

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    Disclosures:
    Endorsing: Ampeg Amps, EMG Pickups
    Time to bust out a chopstick or similar wooden stick (don't use metal for obvious reasons), take off the back and and turn it on plugged into a cab and start lightly tapping tubes till you find a culprit.
  4. B-string

    B-string Supporting Member

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    Um, I would caution against doing the tap test when you have a tube that could be dropping emission when heated.
  5. Altarsmadness91

    Altarsmadness91

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    Am I listening for a certain noise by tapping on them? Not quite sure...
  6. JimmyM

    JimmyM Supporting Member

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    You would know best, but why is that? How about if you keep the volume low?
  7. JimmyM

    JimmyM Supporting Member

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    I would suspect a tube in that bad of a shape would make loud crackling sounds when you tap it. But now that B-string cautioned against it, I'd wait until he explains further why not to do it. He's a tech and I'm not. But I have used that method successfully to detect bad tubes without the benefit of a tube tester.
  8. B-string

    B-string Supporting Member

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    You don't know the failure mode of the tube. If it is a bad weld or sagging control grid volume won't matter. You really don't want to risk a tube shorting and cooking other components. Sub'ing in known good is best here and one time a tube tester would help find the bad one. This is a drop in emissions not a noise issue from what the OP described.

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