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I fried my svt6, need advice

Discussion in 'Amps and Cabs [BG]' started by epilis, Jul 8, 2012.

  1. epilis


    Nov 15, 2009
    Austin TX
    It happened during practice a few days ago. I was using someone else's cab and the volume dropped. I smelled a burning smell. I tested it with a PA speaker and there wasn't any sound.

    The reason it dropped out in the middle of practice is because we rented a huge hourly room and I wasn't plugged into the PA so I maxed my head... I know, that's what I get for maxing it out with someone else's can. I burnt that cab btw.

    Took it home, top cover off, turned it on, no burning smell.

    Just now tried it with my 410hlf and there is berely any sound coming out of it.

    -The relay clicks after a few seconds of powering up.
    -All the knobs and switches seem to respond even though I can berely hear it.
    -The peak light goes with my playing when maxing the gain out.
    -Both fans in the power supply are spinning.
    -All 6 preamp tubes appear to glow normal.
    -When trying both outputs while holding the bass strings, I felt current go through my fingers so I know it's got power.

    Any ideas what needs to be replaced in order to fix this?

    Edit: it pops really loud when I shut it off.
  2. epilis


    Nov 15, 2009
    Austin TX
    Just tried the preamp out into a PA and that works. So it seems like its the power section?
  3. lowfreq33


    Jan 27, 2010
    Endorsing Artist: Genz Benz Amplification
    That would make sense. But listen, we can try and guess what it is all day, you're still going to have to take it to a tech.
  4. The amp will still run and not blow fuses?
  5. jmattbassplaya

    jmattbassplaya Looking for a gig around East Islip, NY!

    Jan 13, 2008
    I feel sorry for your friends cab...
  6. Have you tried an instrument cable from effects send to effects return. Could just be coincidence that it went dodgy after you burnt the cab. You can plug your bass into the effects return to test also (the volume will be really low though).
  7. epilis


    Nov 15, 2009
    Austin TX
    I will try the fx loop trick. I was hoping someone would've said they did the exact same thing and to just replace the output transformer/power supply, but it looks like taking it to a tech is the proper route.
  8. No output transformer in the 6 and the power supply is still operating or the preamp would be dead and/or blow fuses.
  9. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    All sorts of stuff could be wrong......

    Unfortunately, it sounds as if you have a fairly massive fry of the output section... If a number of mosfets have failed shorted, other parts around them often open up and prevent the unit from blowing the breaker, despite the shorted mosfets. if enough have gone, no sound may get through.

    Since there are two sides, slaved in bridge, one side can have failed completely and the other might still be OK, yet you will get no sound.

    if you hear just ONE relay, possibly one side is good. if you hear BOTH relays, then anything might be wrong, from a bad connection in output to massive failures..

    tech time.
  10. Growly Lytes

    Growly Lytes

    Dec 4, 2009
    Downunder Oz
    Bass player
    When switching it off it thumps should mean that there is a DC problem ?
  11. practice quieter....
  12. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    Not if the relays close...... they are "looking for" DC, and open if there is more than a little. But you'd hear the thump before the relays open. At turn-off they will open anyway, so no information.

    But if the relays close with a LOAD, that might be one thing, If they STILL close with NO speaker, that means there really isn't much of a DC problem. The speaker load will short the weak drive output and make it seem as if there is no DC. Without it, that is when you see if there is a basic DC issue.

    There is a biasing circuit that is still DC connected through even if the mosfets are all open, which could be the source of a thump.....(as well as any DC problem) and the drive tubes will put a small signal out.

    We are all guessing.... perhaps educated guesses in some cases, but still guesses....

    it could be something stupid and simple, OR it could be a very bad problem...... A tech can determine that definitely, no guesses..
  13. Alex1984


    Jan 16, 2010
    +1, maxing out on a SVT-6 at practice is unimaginable for me...
  14. +1 I wonder if the OP still has ear drums???
  15. JxBass

    JxBass Supporting Member

    Aug 5, 2008
    Step #1: replace friend's cab :crying:
  16. Step #2: Get hearing aids cause you are now deaf?? :eek:
  17. I'd love to know what cab you were running the amp through.
  18. Guess there's just one thing to say: Tech time!

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