Can I mix 6L6 power tubes?

Discussion in 'Amp Tech Center' started by klasher, Apr 28, 2016.

  1. klasher

    klasher Tele-Holic

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    Hi all, I need to order a 6L6 power tube to replace an old one that rattles. The pair in there are Groove Tubes 6L6GE. Is it safe to order one 6L6GC to replace just the one tube that's rattling? I know its not optimal, but is it safe?
     
  2. bigben55

    bigben55 Friend of Leo's

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    What amp?
     
  3. xafinity

    xafinity Friend of Leo's

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    I aint no expert but I would buy a MATCHED PAIR. Mark the old good one to keep for a emergency spare, use the rattle one for trouble shooting.
     
  4. Johnny Cache

    Johnny Cache Former Member

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    Usually it's best to replace pairs of power tubes since they tend to wear out the same. Some people prefer matched tubes and others don't care but as far as harming your amp it shouldn't be a problem.

    Why not use the good one for trouble shooting? I usually ditch problem tubes, not worth keeping, unless it's a rare tube.
     
    Opaltone likes this.
  5. JD0x0

    JD0x0 Poster Extraordinaire

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    It technically can be done. Guitar amps dont need matched tubes or a perfectly matched bias. In fact, a slight mismatch could reduce the 2nd order harmonic cancelation in the output of a push-pull tube amp and potentially sound better to some ears. The components need to be rugged enough to handle the extra stress, though.

    That being said, it makes way more sense to just buy two new tubes. Tubes are items that will need to be replaced, so it's better to have some extra ones on hand. Get a new set, and keep the other tube, that still works, as a spare.

    Many 'matched' tubes are kind of nonsense, anyway. New tubes will drift as they 'burn in' and mismatch themselves, so many power amps are not as balanced as we assume them to be.
     
  6. robrob

    robrob Poster Extraordinaire Ad Free Member

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    Like you say, it's not optimal but it is safe.
     
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  7. BobbyZ

    BobbyZ Doctor of Teleocity

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    When I got my BFDR from its second owner he said the only problem he ever had was a tube about 1973. So the TV shop replace it for him. It had one RCA 6V6 GTA and one (USA) Tung-Sol 6V6.
    Amp sounded great and that was in 2010. :)

    I prefer to buy matched set but they do definitely drift apart after awhile. The nos RCA 6V6 GTA I put in that amp were a perfect match when they went in there but are now off by a few ma.
    I'm still running them.
     
  8. jazzguitar

    jazzguitar Tele-Afflicted

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    You can do that and it is safe but like replacing one bad tire of 4 used, worn ones, it may result in the older tube wearing differently to the new one.
     
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