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Tube Life: 6V6's, 12AT7's

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by jamison162, Jan 28, 2008.

  1. jamison162

    jamison162 Member

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    NOS Mullard 12AT7's in Reverb and FX applications; how long should they last; key word being should?

    6V6's running 400 pv's. Specifically EH's. I was gonna check the bias on them when I first got the RV50 but never did. It's getting close to a year with those and I'm thinking I'm starting to notice same negative changes in tone, clarity. Kind fizzier, flat and harsh sounding. Avg. 3-4 hours a week on them.

    Thanks
     
  2. phsyconoodler

    phsyconoodler Member

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    The AT's will last for many years and the V's should last a couple three years or more,depending on bias current.
    You need to rebias after a while anyway,so check your bias and rebias if necessary and listen again.If they don't sound any better turf 'em.
     
  3. Blue Strat

    Blue Strat Member

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    What phsycho said, except that it's impossible to predict how long power tubes will last if you don't know the bias setting. Could be anywhere from minutes to years.

    In general, figure 500 hours for new production power tubes (except EL84s which typically won't last as long).
     
  4. GearHeadFred

    GearHeadFred Member

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    I was surprised at how much my sound improved by replacing the reverb driver. I'm not a "swimming in reverb" type guy either.. But the tone of the reverb went from harsh to musical with a different 12at7 in V3.
     
  5. Blue Strat

    Blue Strat Member

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    Which 2 12AT7s did you use?
     
  6. GearHeadFred

    GearHeadFred Member

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    I went from a recent Chinese 12at7 to a OOS (old old stock!) GE 5814.

    I thought the lower gain would make the reverb knob more usable. Honestly the gain seems about the same, but the tone is much nicer; more musical; less metallic.
     
  7. slider313

    slider313 Silver Supporting Member

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    A 5814 is a 12AU7
    As a general rule, I change power tube after a year of regular use.
     
  8. The Pup

    The Pup Supporting Member

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    I have JJ ECC83, ECC82, EL84 tubes that are running at over 6,000 hours (circa mid '90s).
     

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