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Amp head causes speaker cones to jerk in and out

Discussion in 'Amps and Cabs [BG]' started by don21480, Jan 31, 2014.

  1. don21480


    Mar 17, 2006
    Very odd but my Markbass F1 head on a couple of recent occasions has made shorting type sounds thru the speakers of the connected cabinet and the speakers jerk in and out violently. It does this even with no instrument cable plugged in. I've been able to determine thru the process of elimination that its not the speaker cable or the cabinet so it must be originating in the head. I don't even know what to call this to send it to a repair center. Anybody got a clue what this might be.
  2. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    It sounds like you might have a high frequency oscillation in the amp. Best not to use the amp while it is doing this.
  3. FunkHead

    FunkHead Supporting Member

    Mar 10, 2007
    Phillipsburg, NJ
    Might start with some deoxit and clean all the cable connections. Maybe try reversing the ground lift.
  4. It could be something as simple as a broken/intermittent component lead. Whatever it is, it doesn't sound like it's doing your drivers any good. Better to see a tech now than later when more damage has been done.
  5. don21480


    Mar 17, 2006
    Nobody locally works on markbass so I'll have to send to one of their service centers - its the drawback to markbass for sure