Best way to determine when you need new tubes

Discussion in 'The Squawk Box' started by irocdave12, Sep 14, 2017.

  1. irocdave12

    irocdave12 Senior Member

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    image.jpeg
     
  2. Dick Banks

    Dick Banks Senior Member

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    When the neighbors stop bitchin'
     
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  3. LPPILOT

    LPPILOT Senior Member

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    Right after you brag about How long the present tubes have lasted.
     
  4. DarrellV

    DarrellV Almost 1 Year old this month! Premium Member

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    When one of your bandmates comments on how cool the blue glow looks in your amp....
     
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  5. KenG

    KenG Senior Member

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    Usually they have to degrade quite a bit before you notice because it happens slowly over time (I'm talking wearing out here not tube failure). Tube testers used to be so common in the 70s and even to degree in the80s and you simply pulled your tubes and tested them. I was in the Miltary back in the 80s as a tech and had access to a nice Stark. Now the only hi voltage testers left are reconditioned ones and theyare expensive. You could probably find plans and build the circuits to test the most common tubes but it would still be expensive. There are low voltage testers out there, or at least there used to be, but they don't test at working voltages so they may miss some issues.
     
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  6. DarrellV

    DarrellV Almost 1 Year old this month! Premium Member

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    Yeah, I remember every Radio Shack had one at the front of the store... Oh, wait! They're not around anymore either!:mad:
     
  7. rogue3

    rogue3 Senior Member

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    I have a nice rack mount unit.Navy tester,i think.That grey colour they used on the US. Navy ships.High voltage.Chicken head knobs:D. It worked last time i used it,which would be probably 15 years. Point to point.I installed it in a home made inclined mahoganey frame.Its a nice display piece.I have the manual,and may boot it up to test some output tubes that went south on me recently in a Hiwatt Dr504.Need to test for shorts.

    Its no biggie to call the ball when the amp starts sounding like uncle donald.As for the slow deline,usually when i become dissatisfied with the sound, that raises a flag.It helps to have other amps around that are in prime condition to compare too, that's my benchmark.And a whack of tubes to substitute.I'm good there.;)
     
  8. ehb

    ehb Chief Discombobulator Premium Member

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    Listen for odd change...

    One of my combos, I started hearing a bit over a second of motorboating very soft in background, gtr output was all normal during it, and it might not happen again for an hour or two...

    Replaced power jugs, rebiased, and no mo moboat..... Very very low dB hiss in clean chan was gone too...
     

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