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Burn marks on tube

Discussion in 'Amp Central Station' started by Brillig, Feb 25, 2021.

  1. Feb 25, 2021 #1
    Brillig

    Brillig TDPRI Member

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    I just pulled this tube and it has smudges that look like burns around it. Is this common?

    20210225_202025 - Copy.jpg
     
  2. Feb 25, 2021 #2
    Engine Swap

    Engine Swap Tele-Afflicted

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    Yes - play yr guitar
     
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  3. Feb 25, 2021 #3
    VintageSG

    VintageSG Friend of Leo's Ad Free Member

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    Yes. If it works and sounds good, make some noise with it.
    Side note : Every EL84 I have that has more than a few months of normal use displays such marks.
     
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  4. Feb 25, 2021 #4
    gkterry

    gkterry Tele-Afflicted Silver Supporter

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    Looks to me like them little electrons in that tube might have had a weenie roast.

    Seriously, it should be fine as long as it lights up & makes the proper guitar type noise
     
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  5. Feb 26, 2021 #5
    Engine Swap

    Engine Swap Tele-Afflicted

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    I've heard this is the result of tiny amounts of oxygen and debris that are in the tube. Even though tubes are a vacuum when manufactured, a tiny amount of oxygen remains. When the tube is first powered-up, the oxygen reacts with any material in the tube and creates the marks. +1 on seeing this on many EL84s.
     
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  6. Feb 26, 2021 #6
    uriah1

    uriah1 Telefied Gold Supporter

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    Now if you see white. You have a problem.
     
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