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Chain output on GK MB212 damaged speakers??

Discussion in 'Amps and Cabs [BG]' started by Oneirogenic, Aug 12, 2016.


  1. Oneirogenic

    Oneirogenic

    Nov 10, 2009
    So I was playing a gig with my Ergo EUB and my GK MB 212 ii using the amp at low volume for stage monitoring and what was supposed to be the DI out from the amp going to the board and mains. Turns out the soundguy plugged his xlr into the chain out instead of the DI out. I did not notice this until the end of the set as the amp was performing fine the whole set and my bass sounded great in the mains. I figured the soundguy just got a really hot or really low signal when I saw he used the wrong output.

    About 2-3 days later I plug in the amp to practice at home. Lots of speaker distortion. The headphone out is clean. Only the top speaker is getting bass sound and its very distorted. Bottom speaker has white noise coming out of it but nothing else. Did using the chain output improperly kill the speakers or something? Anyone assistance is greatly appreciated.
     
  2. Nighttrain1127

    Nighttrain1127 Supporting Member

    Nov 27, 2004
    Near Worcester MA
    It could have caused all kinds of Issues if he used the Phantom power on the board.
     
  3. If you made it through the gig where the sound guy was plugged into your chain out rather than the DI and all was fine with your amp throughout the show, it is hard to imagine the PA being plugged into the chain out as having anything to do with the speaker problems now. In other words, if there was a problem with doing what was done, it should have presented itself immediately at the start of the gig.
    The chain out comes from a point before the power amps. The headphone out is after the power amps and essentially connected to the speakers.
     

    Attached Files:

  4. The chain out in the drawing I provided in my earlier reply shows a capacitor in line. I assume this is to prevent DC voltages from getting back in to the amp. This would be easier to sort out with a real schematic rather than a line drawing of the signal paths. I can't totally rule out phantom power, but it seems highly unlikely to me.
     
  5. Oneirogenic

    Oneirogenic

    Nov 10, 2009
    So it's probably a coincidence that my speakers crapped out right after this connection mistake?
     
  6. Nighttrain1127

    Nighttrain1127 Supporting Member

    Nov 27, 2004
    Near Worcester MA
    I would contact GK tell them what happened and what is going on with your amp they have better knowledge of their equipment and design and should be able to steer you in the right direction to taking care of the problem. No slight directed at anyone here with those comments Just that GK would be in a much better position to figure it out.
     
    Old Garage-Bander likes this.
  7. Well just to be clear.
    Did the problem arise at the time the sound guy plugged in?
    I was under the impression that everything was fine during your gig and you only noticed something wrong a couple of days later.
     
  8. Oneirogenic

    Oneirogenic

    Nov 10, 2009
    You are correct, the amp was fine the whole time it was plugged in the wrong spot during the gig.
     
  9. You can shoot a person and he can die three days later.
    Not so much with amps, especially SS ones. They die from being shot (doing something you shouldn't) right away or not at all.
    Have you tried cleaning the I/O Jacks? (Effects in/out) Or run an instrument cable from out to in?

    EDIT: No maybe not that after all. You said it sounded OK in headphones. Sorry.
     
    Last edited: Aug 12, 2016
  10. Oneirogenic

    Oneirogenic

    Nov 10, 2009
    No effects loop.
     

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