Comet 20: Do I need to change rectifier tube?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Grun, Jul 14, 2008.

  1. Grun

    Grun Member

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    I am about to change out the tubes in my Tone King Comet 20 (ser #50). The tubes have never been changed over the 4 or so years I have owned the amp, and it has lately developed a loud random crackle which I am hoping will be cured by renewing the tubes (3 X 12ax7a, 2 X 6v6, 1 X 5ar4).
    I read somewhere that rectifier tubes rarely fail. Should I replace it anyway, or would that just be a waste of money? It's at least 4 years old. I use the amp twice a week for several hours at a time.

    Thanks.
     
  2. conundrum

    conundrum Member

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    If you do decide to replace it, I would only replace with a NOS tube.
    Plugging in an unknown new production GZ34 is Russian Roulette.
    The initial startup blowout on these things are insane, regardless of brand.
    Sometimes it's best to leave well enough alone.
    Only sometimes though...
     
  3. Grun

    Grun Member

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    OK, I will answer my own question on this one, or rather I will provide a
    summary of the response I received from Mark Bartel at Tone King. Mark did
    not recommend changing the rectifier tube. Interestingly he also recommended
    installing an EH AX7 in the #1 pre-amp spot and 'long plate' Sovtek AX7'
    (LP's) in the remaining 2 spots. This because the microphonic
    characteristics of the long plates render them unsuitable for the #1 spot.
    He also reiterated his recommendation of EH 6V6's as specified in the amp
    manual.
    So I did not order a new rectifier. If it turns out to be an issue I have a
    spare on hand that came out of my VOX AC 30 that was fairly new, and
    probably did not really need to be changed either.
    Thanks to those folks who responded and maybe this info will be useful to
    someone else. Mark turned my email around in less than a day. Very nice.
     
  4. Blue Strat

    Blue Strat Member

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    NOS rectifiers rarely fail. New production rectifiers fail much more frequently.
     
  5. trey85stang

    trey85stang Member

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    Are you serious? :NUTS
     
  6. Blue Strat

    Blue Strat Member

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    LOL. I love those CHIAN tubes.

    CHIAN. Isn't that a Spanish/Native American tribe? (no offense intended to ANYONE).:rotflmao
     

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