pulling power tubes to lower headroom

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by Eagertone, Apr 27, 2005.


  1. Eagertone

    Eagertone Member

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    So I just got a TopHat Ambassador 2x12 combo. It runs 4 6V6s for 35 watts. I've heard, but never tried, that you can pull the power tubes in sockets 3 and 4 (the outer 2) to reduce power to 1/2 power. Anybody know if this will work with my amp? I'd like to hear from somebody that knows more than I do before I go blowing her up. She's much to pretty, far too expensive, and simply much too young to die.

    Thanks.
     
  2. alderbody

    alderbody Member

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    When pulling out power tubes make sure you always do it for the two inner or the two outer ones (it doesn't matter)

    But that's for fender amps, and that's what i did on my twin reverb.

    I believe it should work, but i'd ask the manufacturer first, if i were you.

    Anyway, don't expect significant loss of volume, cause in the non linear audio reality, half power doesn't mean half volume.

    You have to go about 1/10 of the power to half the volume.

    Expect a "grittier" and "dirtier" tone because the two remaining tubes will handle the load of four.

    But again, don't do anything unless you ask.

    good luck
     
  3. alderbody

    alderbody Member

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    plus, your tubes will wear out faster...

    (...but anyway, it sounds good on the twin...)

    ;)
     
  4. Blue Strat

    Blue Strat Member

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    In general, this works with 4 power tube amps but in some 4-6V6 amps one pair is run cathode biased and the other as fixed biased. Best to check with the manufacturer.

    BTW, dropping the power to half will be barely noticeable.
     
  5. HeeHaw

    HeeHaw Member

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    +1. I did this in one of my 100 watt Marshalls and barely noticed any difference. I really didn't think it even sweetened anything either. I ended up putting THD Yellowjackets in it, to get reasonable volume levels out of it.
     
  6. el34power

    el34power Member

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    Speaking of the jackets. Can you give me your impression of the tone change and so on.
     
  7. Eagertone

    Eagertone Member

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    I use yellow jackets in my 6L6 amp and love it. The tone did change, it's got a lot more highs now. More glassy and crisp that the big and fat (as it used to be). The break up is beautiful though.

    I also tried a THD hotplate, but it really is a tone killer and completely unusable at anything past -4dB.


    I have an opportunity to by a Club Reverb, I may just buy that one and use that for lower volume settings.
     
  8. Eagertone

    Eagertone Member

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    sorry... club royale. there's not reverb on it. that was what was on my mind, so my fingers typed it. :D
     

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