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Did my son fry my Amp and can it be repaired?

Discussion in 'Pickups & Electronics [BG]' started by Lancerator, Dec 15, 2013.

  1. Lancerator


    May 26, 2009
    Well my son was up late trying to do some recording and out of sheer lack of sleep or forgot what he was doing he accidentally plugged the the speaker output of my Ashdown MK500 amp(1/4 jack) into a unbal/bal input of his mixer. Anyway when he realized his error he unplugged the connection from his mixer which arced he said. Now when we plug the amp into the cab and just turn on the amp we get a huge blasting hum. Is the amp blown or just the transformer. Any thoughts would be appreciated.

    I posted this in another section that I think was the wrong section. Hope this is the right section, Sorry moderators :)
  2. mrb327

    mrb327 Supporting Member

    Mar 6, 2013
    Nobody Knows
    SUbbed just as a learning experience

    Do you have another amp to test to?
  3. If this is a tube amp, you probably blew the tubes by running a high impedance load. The output transformer is fine, but you'll need to retube the power amp section.
  4. Lancerator


    May 26, 2009
  5. Lancerator


    May 26, 2009
  6. C130AVN

    C130AVN Stringed Tubist

    Apr 19, 2012
    Winnipeg, MB

    Actually high voltage flyback within the Output Transformer (OT) is a greater concern when faced with a high or infinite impedance load and the coil windings can fry. I had a MusicMan guitar amp die that way.
  7. Steve Dallman

    Steve Dallman Supporting Member

    If the amp was on when he pulled the plug, he may have shorted the plug as it came out. So briefly, the amp saw a dead short, and that's what damaged the amp.

    It's a 500 watt SS amp. SS amps don't like shorts.
  8. grendle


    Mar 4, 2011
    Central FL
    500w to the mixer should have blown the mixer. Granny's take a lot of heat before they burn open. Sounds like a shorted transistor or fet in the output section. Shouldn't be too bad of a repair cost wise even if he blew the whole bank. Most likely it's the first or last one that blew, they may be a matched set like ampeg uses, so you may have to replace the whole bank ( probably 5 transistors). Get it to a tech and see what the damage is.
  9. there will be damage to the driver to.

    Hum on the output suggests the output stage may be sswung and leaking dc. Please check to make sure it isn't before you plug it into another cab
  10. Steve Dallman

    Steve Dallman Supporting Member

    The input impedance of the mixer would be somewhere between 1k and 50k ohms. How much power would a SS power amp develop into such a high impedance. Probably not enough to blow anything. I'm sticking with the short theory.
  11. BawanaRik


    Mar 6, 2012
    New Jersey
    It's Christmas.

    Go buy another bigger better one.

    You deserve it!
  12. Lancerator


    May 26, 2009
    thanks all for all you suggestions and help. Ill call a tech tomorrow and see when I can get it in. I hope my bergantino cab is ok also.
    Ill let you know what transpires.
  13. Hope it doesn't set you back too much.

    If it were my son, you wouldn't find me doing any dishes or laundry for a very long time. I'm just sayin...