Do I need to rebias if I just interchange the two 6V6 on BFDR?

Discussion in 'Amps and Cabs' started by steve_chiro, Sep 21, 2008.

  1. steve_chiro

    steve_chiro Member

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    Hi guys,

    Quick question: My 66 BFDR has 2 6v6, I need to check something out tube-wise. Do I need to rebias the amp if I just swap the two (ie, just put one in the other's socket et vice-versa--not replace them)?

    Thanks!!!

    P
     
  2. GuitarsFromMars

    GuitarsFromMars Member

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  3. Dave C

    Dave C Gold Supporting Member

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    No, the bias setting is the same for both tube sockets so you can swap back and forth, but it certainly wouldn't hurt to check it as tubes do drift with age.
     
  4. riffmeister

    riffmeister Gold Supporting Member

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    The CBS era DR's had a balance control instead of a bias control. The balance control changed the relative bias between the two tubes (non-matched tubes could thus be biased to minimize hum). The BF amp's bias control affects each tube the same way as Dave C notes.
     
  5. GuitarsFromMars

    GuitarsFromMars Member

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  6. Blue Strat

    Blue Strat Member

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    Sorry, no. The DR bias control NEVER changed. It was always a bias control and never a balance control.

    Yes swapping tubes is ok without a rebias. Even a temporary swap of DIFFERENT 6V6s is ok...just don't leave them in for too long.
     
  7. riffmeister

    riffmeister Gold Supporting Member

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    The expert has spoken! :D

    Which models had the balance pot?
     
  8. Blue Strat

    Blue Strat Member

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    Most of the others that had any bias related pot at all. In fact, I'd venture to say all of the others.
     
  9. riffmeister

    riffmeister Gold Supporting Member

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    Huh, I wonder why the DR 'escaped' the change to the balance pot.
     
  10. steve_chiro

    steve_chiro Member

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    Wow. Great info. Good to know.
    Thanks so much guys.
    P
     

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