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problem with a M2000

Discussion in 'Amps and Cabs [BG]' started by Uziel, Apr 10, 2009.

  1. Uziel


    Sep 2, 2003
    my M2000 is doing a strange thing :
    i tried to swap the tube (2x mesa and 1x sovtek) for some new 12ax7 EH...
    when i put the EH on, i got almost no sound from the head, except if i remove the 2 preamp tubes (but not the driver one) and in this case i get the normal sound and volume from the FET chanel... and when i put the old tubes back, it don't work if there is an EH tube on the head !
    and if i remplace the EH by a mesa or sovtek, it work...

    i need help !
  2. jastacey

    jastacey Supporting Member

    Feb 8, 2009
    You've got bad tubes ...send them back ... I don't know if the m-2000 has a bias for the preamp section ... I don't have a wiring diagram
  3. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    Why would any amplifier have a bias control for the pre-amp?? I agree that the OP most likely has bad tubes.


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