Whens the RIGHT tubes replecement time

Discussion in 'The Squawk Box' started by picoman, Feb 8, 2015.

  1. Paragon

    Paragon Senior Member

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    Indeed. The chances of tubes aging the same is slim. Some places will burn them in to reduce the amount of drift.. of course you pay for it.

    In the end, as long as the tubes are properly biased, matched/unmatched doesn't matter. My guess is that you will get a greater difference in tone from different brands of tubes than matched/unmatched.
     
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  2. EndGame00

    EndGame00 Senior Member

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    When I used to gig regularly, I only did a full retube on my Mesa just twice and I used to ran the amp hard.
     
  3. mdubya

    mdubya Senior Member

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    Keep a spare set. Only change them if one dies or sounds bad. Otherwise, let 'er rip.

    There is no need to change them unless there is a problem which needs to be addressed.
     
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  4. ScottMarlowe

    ScottMarlowe Senior Member

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    Matched means they have the same bias point and response curve, or very close. For audiophile stereos maybe it's nice. For guitar amps it's pure snake oil.
     
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  5. RAG7890

    RAG7890 Premium Member

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    + 1, this is important. :thumb: :applause:

    Not all Amps are equal. Hit the Tubes with very high Plate Voltage & you get killer tones (loads of even order harmonics) but the Tubes do not hold up as long.

    IMHO the tone is more important that how long the Tube lasts.

    For example, the Bogner Shiva runs very high plate Voltages so very hot & therefore, a shorter life span is to be expected.

    :hmm:.........................so if anyone has a Tube in a Pedal, running off a 9 Volt Battery it will last about a millions years. :laugh2:

    :cheers:
     
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  6. RAG7890

    RAG7890 Premium Member

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    Just for laughs I had to put this one in as I am sure most of you have never seen the venerable 4CX 10000. :wow:

    We used to recondition these suckers at AWA in Sydney in the 1980's. I worked on these & used to check how well the carburising was performed on the tungsten filaments under immense Vacuum (to produce Tungsten Carbide).

    That was in the fun days when we made all sorts of great stuff. We were one of ~ 9 locations in the World that could pull this Vacuum, which is a must when Valves are sealed under Vacuum to ensure efficient thermionic performance.

    For those that are interested this Valve puts out 10,000 Watts. Enough to fill a Stadium. :laugh2:

    These were used by National Radio ABC for broadcasting all over Australia & for Military applications in HF Amps.

    If any of you saw the NOS Valve Store we had, your mind would have, well simply imploded. :wow: :wow: :wow:

    About the size of two Bowling Balls & heavy. The Body is Ceramic, with massive Cooling Fins.

    [​IMG]

    :cheers:
     
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  7. rabidhamster

    rabidhamster Senior Member

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    When could be a better time than right now?
     
  8. picoman

    picoman Senior Member

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    And what if my fues is Dead and I dont know that...:slash:


    Thanx for opening my eyes on PREMIUM MATCHED PAIRS :thumb:


    Is there any difference in sound if your running 2 power tubes that are brand new with 2 power tubes that lets say have 30% life in them left....compare that to the full new set....I mean is it stupid if one of you tubes dies and other still have life in them...need to replace the whole set...


    Man couldnt they make like an "duracel check test" for bateries
    https://www.youtube.com/watch?v=k6Gz5Gom5NI

    :naughty:
     
  9. InsertUsernameHere

    InsertUsernameHere Senior Member

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    That's awesome as hell. Get Marshall on the line, I've got a great idea.

    :slash:
     
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  10. bilbarstow

    bilbarstow Premium Member

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    RAG7890,

    You bring back memories for me with this picture. Back in the late 70's I worked at Varian - actually BUILDING these types of tubes and even BIGGER ones. We made them for MIL use as well as Klystrons for X-Ray use and really big (some were 6 foot long :wow:) high power transmission tubes for Radio and TV broadcasting use. My job was to braise them together in hydrogen vacuum Retort furnaces at up to 2100 degrees F. That was a great job, paid for my college education !

    That little cap at the top that covers the vacuum pull-down nipple ? I must have arc-welded on about 100000 of them.
     
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  11. Marshall & Moonshine

    Marshall & Moonshine Senior Member

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    When do you replace one tube rather than both (in a pair)?
     
  12. THDNUT

    THDNUT Senior Member

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    I always imagined this is what a flux capacitor would look like. :laugh2:
     
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  13. picoman

    picoman Senior Member

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    You mean If one of my tubes goes Dead I nead to replace two of them:shock:
    I curently have 4 x JJ EL84 power tubes.
    Why cant I replace just one that gone dead?
     
  14. THDNUT

    THDNUT Senior Member

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    you can
     
  15. picoman

    picoman Senior Member

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    I Know I can and I did.
    BUt why did Marshall & Moonashine said change a pair...
     
  16. THDNUT

    THDNUT Senior Member

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  17. Marshall & Moonshine

    Marshall & Moonshine Senior Member

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    No, no, no....
    I asked.....;)
    And I'm just talking about pairs, as I've no use for quads.
    If only one tube is bad, should you replace the pair, and does it make a difference if it's fixed or cathode biased?
     
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  18. northernguitarguy

    northernguitarguy SWeAT hOg

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    I'd like to know this as well. Do unmatched power tubes make a difference in an amp? The manufacturer always seems to say the pair needs to be matched in a cathode biased amp.
     
  19. Soul Tramp

    Soul Tramp Speaker Snob V.I.P. Member MLP Vendor

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    Far worse than that can happen with a blown power tube. Things like a cooked transformer and other scorched components.
     
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  20. johan.b

    johan.b Senior Member

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    Can happen, sure. But as long as the user doesn't replace a blown, sensible shosen fuse with something less .. eh. .fusible, it rarely does.
    12years repairing amps for a living, three of them fulltime for Marshalls scandinavian distributor, with very few exeptions the only time i needed to replace an output transformer was when someone replaced the fuse with something beefier.
    I'm not disputing you, shit happens, but a good design blows the fuse, not the iron
    J
     
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