What power tubes to feed my Traynor YBA 1a?

Discussion in 'Amps and Cabs [BG]' started by nrandall85, Apr 29, 2014.


  1. nrandall85

    nrandall85

    Apr 29, 2014
    Hey everyone,

    I have a friend doing some cap work on my '72 Traynor YBA 1a. It's running original power tubes, which may need replacing. I'm looking for something current production that can take the high plate/screen voltage of this amp- since there's no way I can afford another pair of Mullard EL34's.

    Anyone have some new production tube success stories with this amp?
     
  2. Primakurtz

    Primakurtz Registered Nihilist

    Nov 23, 2011
    Denver, Colorado
    I recently put a pair of JJ 6CA7s in mine, and they sound good. Lord Valve says they are plenty sturdy enough for the YBA-1a.
     
  3. nrandall85

    nrandall85

    Apr 29, 2014
    Did you have to change anything in the amp, or did they just drop in?
     
  4. coreyfyfe

    coreyfyfe Supporting Member

    Nov 19, 2007
    boston, ma
    EHX has a 6CA7 that's supposed to be decent. Haven't tried the JJ. I had a musicman HD130 that ran 6CA7s or EL34s and I think that might have been the tube that I put in there when I retubed it, but I'm not 100% on that. It was some kind of sovtek, but I don't recall if the shop went with the 6CA7 or EL34. Every time I had an amp with EL34/6CA7s it was always brighter than I like for bass amps, but that's probably more in the preamp designs of those amps than the fact that they had that type of output tube.
     
  5. coreyfyfe

    coreyfyfe Supporting Member

    Nov 19, 2007
    boston, ma
    The amp schematics call for 6CA7s. They very similar to EL34 but can handle a bit more voltage. Something that calls for 6CA7s usually has higher voltages that might not work with wimpy EL34s.
     
  6. Primakurtz

    Primakurtz Registered Nihilist

    Nov 23, 2011
    Denver, Colorado
    I did bias them, as always when changing power tubes.
     
  7. gary m

    gary m

    Jan 17, 2011
    Mid -Atlantic
    Also look at tubes from Tube Amp Doctor, Ei and Winged C. I like Antique Electronic Supply's website: www.tubesandmore.com
     
    SirMjac28 likes this.
  8. BassmanPaul

    BassmanPaul Inactive

    Disagree Corey. There's nothing about the EL34 that's "wimpy". The EL34 has a plate rating of 800V. With their screens regulated, a pair will deliver in excess of 70W. The suppressor grids, pin one, should also be returned to the raw negative bias supply as this adds stability to the output stage.
     
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