/ Register

  1. Win a Broadcaster or one of 3 Teles! The annual Supporting Member Giveaway is on. To enter Click Here. To see all the prizes and full details Click Here. To view the thread about the giveaway Click Here.

Retubing/biasing

Discussion in 'Amp Central Station' started by ty.vaughn777, Feb 13, 2013.

  1. Feb 13, 2013 #1
    ty.vaughn777

    ty.vaughn777 TDPRI Member

    Posts:
    18
    Joined:
    Feb 13, 2012
    Location:
    Pennsylvania
    So I have recently purchased a peavey classic 30 and the tubes were removed from the amp and shipped separately for safer shipping........
    When I put them back in, do I need to do anything as far as rebiasing or anything special or can I just plug them back in and go?
    If something does need to be done, how do I go about it?
    Thanks
     
  2. Feb 13, 2013 #2
    rsi106

    rsi106 TDPRI Member

    Posts:
    97
    Joined:
    May 27, 2010
    Location:
    California
    I am pretty sure that amp is cathode biased. No biasing necessary.
     
  3. Feb 13, 2013 #3
    telex76

    telex76 Doctor of Teleocity Ad Free Member

    Age:
    69
    Posts:
    16,123
    Joined:
    Jun 24, 2006
    Location:
    Fort Worth,Tx.
    You can take the same power tubes out and put back in without having to rebias.
    That's assuming it was biased properly in the first place.
    When you change to a different set of power tubes thats when they need rebiasing.
     
  4. Feb 13, 2013 #4
    ty.vaughn777

    ty.vaughn777 TDPRI Member

    Posts:
    18
    Joined:
    Feb 13, 2012
    Location:
    Pennsylvania
    Ok cool thanks guys!
     
  5. Feb 13, 2013 #5
    telex76

    telex76 Doctor of Teleocity Ad Free Member

    Age:
    69
    Posts:
    16,123
    Joined:
    Jun 24, 2006
    Location:
    Fort Worth,Tx.
    It is fixed biased, but has no adjustment pot.
    Only way to adjust bias is to change the bias resistor. You could always mod it with an adjustment pot.
    If you always use the same brand of tubes you can probably get by without ever adjusting bias when you change them, but you may not ever know the best performance of your power tubes and it could shorten thier lifespan.
     
  6. Feb 13, 2013 #6
    BiggerJohn

    BiggerJohn Friend of Leo's

    Posts:
    3,311
    Joined:
    Jun 1, 2009
    Location:
    California
    +1. fixed, non-adjustable bias.

    Not all EL84 amps are cathode biased.
     
IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.