Bad Phase Inverter

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Dave B, Sep 17, 2004.


  1. Sep 17, 2004 #1
    Dave B

    Dave B Exit... Dual Stage Left Silver Supporting Member

    Messages:
    1,442
    Joined:
    Oct 16, 2003
    Location:
    South Central PA
    What are the symptons of a phase inverter going bad? If it does go bad, does it go gradually, or does it go pretty much immediately? I just replaced a microphonic preamp tube and was curious what I should be on the lookout for, because if the preamp tubes go bad, then I guess the PI will eventually, too.
     
    Dave B, Sep 17, 2004
    Dave B, Sep 17, 2004
    #1
  2. Sep 17, 2004 #2
    Blue Strat

    Blue Strat Member

    Messages:
    29,981
    Joined:
    Aug 2, 2002
    Location:
    Sterling, VA (not far from Washington DC)
    There's no simple answer to this question. It could go gradually or suddenly. It only takes a second (or less) for almost anything to stop working.

    Symptoms could be loss of power, high distortion, no sound, etc.
     
    Blue Strat, Sep 17, 2004
    Blue Strat, Sep 17, 2004
    #2
  3. Sep 22, 2004 #3
    Roccaforte Amps

    Roccaforte Amps Member

    Messages:
    6,120
    Joined:
    May 23, 2002




    A bad PI tube in most cases will reduce output.
    What usually happends is one side of the tube
    goes bad increasing even order harmonics,
    so the amp becomes cleaner sounding.
     
    Roccaforte Amps, Sep 22, 2004
    Roccaforte Amps, Sep 22, 2004
    #3
  4. Sep 22, 2004 #4
    Dave B

    Dave B Exit... Dual Stage Left Silver Supporting Member

    Messages:
    1,442
    Joined:
    Oct 16, 2003
    Location:
    South Central PA
    Thank you both for the info. Good stuff to know.
     
    Dave B, Sep 22, 2004
    Dave B, Sep 22, 2004
    #4
  5. Sep 23, 2004 #5
    Wakarusa

    Wakarusa Member

    Messages:
    1,477
    Joined:
    May 7, 2004
    Location:
    Newnan, GA
    Also, just like any other tube going south, they can start to pop and spit and/or do the "frying bacon" thing.
     
    Wakarusa, Sep 23, 2004
    Wakarusa, Sep 23, 2004
    #5

Share This Page