6L6 tubes' glowing color

Discussion in 'The Squawk Box' started by kryho, Mar 9, 2009.

  1. kryho

    kryho Member

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    Hello, I have a question - 6L6 tubes in my Mesa Roadster glow red, while in H&K Triamp glow blue. Does that mean that ones of them are worn, if so, which ones?
    THX:cool:
     
  2. Loko

    Loko Senior Member

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    I read somewhere that some tubes let in a little oxygen to work properly and this causes them to glow blue. This is only on certain amps and I don't know if yours is or not.
     
  3. slowhand0461

    slowhand0461 Senior Member

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  4. kryho

    kryho Member

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    well, not red but rather orange...sound is pretty ok, and bias is switchable 6L6-EL34 and is set as should be.
    Slowhand, thanx for the links, very useful.
     
  5. kryho

    kryho Member

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    Oh, one more thing- is it possible in this particular amp to take out two power tubes so that it runs only on two? It's not the matter of reducing the power because it has 50\100 switch but I have only two spare EL34 and would like to try them instead 6L6. If so, which ones can I take out? inner two or outer two?
    Thanks:naughty:
     
  6. ES350

    ES350 Senior Member

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    Tubes would not operate for long 'if they let in oxygen'. If the plates are glowing bright red/orange, the tubes are toast and take it to a tech; bias or power supply/regulation problems. Blue is fine...
     
  7. Joeydego

    Joeydego your mom is a nice lady V.I.P. Member

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    a orange hue and the filament orange has never been a problem for me. If its glowing like a light bulb, Id say turn it off. at any rate, perhaps its time for a tune up one way or the other????
     
  8. Loko

    Loko Senior Member

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    Yup, was thinking mercury not oxygen... my bad...

    Mercury vapor haze is a blue glow which is noticeable between the plate and
    filament in Types 82 and 82 rectifier tubes. These are the only types of
    Sylvania receiving tubes in which this type of haze appears. The perfect
    operation of Types 82 and 83 is dependent upon a mercury vapor which comes from
    free mercury that has been placed in the bulb during the exhaust period.
    Therefore this type of blue haze is in no way detrimental to the operation of
    these tubes.


    Gas is a blue haze which is usually confined to the vicinity of the plate and
    filament structure. Its presence, when of large content, affects the operation
    of a receiver to the extent that erratic performance is noticeable. Gaasy
    tubes should always be replaced with new tubes.
     
  9. kryho

    kryho Member

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    Ok, I'll show you some pics:
    [​IMG]
    [​IMG]
    [​IMG]

    no blue, just red-orange...
    what do you think?
    The last one is with accidental reflection so don't take this one into consideration...
     
  10. jo07

    jo07 Senior Member

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    looks good to me
     
  11. slowhand0461

    slowhand0461 Senior Member

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    Lookin' good!!!!:thumb:
     
  12. kryho

    kryho Member

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    THANK GOD!!!!
    I was scarred somethin' gonna blow...:wow:
     
  13. ES350

    ES350 Senior Member

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    Philips 7581A's typically have a nice violet blue glow to them...nothing wrong with those.
     

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