Tube tester???

Discussion in 'The Workbench' started by Sg-ocaster, Jul 27, 2020.

  1. Sg-ocaster

    Sg-ocaster Active Member

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    Ok been thinking on buying a tube tester as I collect and love rolling tubes.But the whole restoration calibration thing has me Leary.Now being as I don't need to test power tubes as I only buy burned in sets or nos from trusted dealers.So shorted power tubes is not a concern.Do I really need a tester?
    As far as preamp tubes 12ax7 specifically....would I be better off buying a cheap tube amp like a valve Jr and a socket saver as a test mule...to just amp test 12ax7s. I won't have a transconductance number rating but I would know microphonics noise and general sound. And I know basically how to tell visually a high mileage tube( dark base...deteriorated flashing ...Smokey glass etc..)
     
    Last edited: Jul 27, 2020
  2. South Park

    South Park Well-Known Member

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    The transconductance is what you want in a tube tester . The rest you don’t need to test for . It would be nice to have one
     
  3. StingRay85

    StingRay85 Active Member

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    Maxi Preamp II? Not cheap though.
     
  4. anitoli

    anitoli Well-Known Member

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    Maxi Preamp 2 is good. I have one.

    A side note on power tubes, even though they may arrive to you matched they may not stay that way. Being able to see what a tube is drawing for current for a bias point is very valuable info. I have saved a boatload by being able to quad up single tubes and run them.
     
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  5. junk notes

    junk notes Well-Known Member

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    I use a trusty Hickok and has made it's money back verifying a good tube, or tubes.
    [​IMG]
    (similar model)
     
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  6. Sg-ocaster

    Sg-ocaster Active Member

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    Bought one.....an old triplett 3413.....not a maxi pre or a vtv triode charecterizer or a tv7 but should give me an idea....gotta go through it and calibrate etc.....
     
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  7. Sg-ocaster

    Sg-ocaster Active Member

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    Been reading on calibrating these and it sounds like a PITA.......so maybe my tried and true method of hold it up to the light and look over the glass and base to get an idea of mileage then plug it in and see what happens may be simpler than dicking with an ancient old peace of test equipment .Guess I'll see.......
     
  8. Yamariv

    Yamariv Well-Known Member

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    I recently purchased a B&K 707 and rebuilt it and calibrated it and it works amazing! It's paid for itself countless times finding more than one auction sellers claims of a good testing tube false and enabling returns. Also, just this weekend I was working on my 5E3 and had problems with arcing in one of the 6v6's due to a faulty bias probe and found that the arcing cooked the 6v6 just by quickly testing it..amp worked but tube tested very very low after that and I would never have known without my trusty B&K :dude:
     
  9. StingRay85

    StingRay85 Active Member

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    I'm losing my patience. I ordered my maxi pre ii 6 weeks ago and now finally it arrived at Belgium customs today. USPS deployed a rowing boat to bring it across the Atlantic I think. In the mean time I pass my time tracking down long plate philips tubes for next to nothing, in the hope they are not garbage.
     
  10. Sg-ocaster

    Sg-ocaster Active Member

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    Row row your maxi pre gently cross the sea merrily merrily merrily merrily hope your mullards sound like a dream.
    Ok guys now 5 part harmony I'll take the root note.....:band:
     
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  11. anitoli

    anitoli Well-Known Member

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    They were slow to ship mine. I think it was built after i ordered it.
     
  12. Sg-ocaster

    Sg-ocaster Active Member

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    Anyone ever calibrate an old emmision tester? I know I need to get a calibration tube. But in reading I guess my triplett 3413 has a calibration pot. But it says must be calibrated using range 1.....what does that mean?? I've never used a tester be for let alone calibrated one.......for years I've done the look at the glass then plug pretubes into the amp and see what it sounds like trick.
     
  13. StingRay85

    StingRay85 Active Member

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    You need to start with finding a good manual, and probably overhaul the whole thing before it even makes sense to calibrate. Or like many tube sellers you'll get magically numbers like "80% --> 127% on this tester = better than NOS!!!) :orly:
     
  14. Yamariv

    Yamariv Well-Known Member

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    OP, congrats on buying the tester! Agree with above, hopefully there are some videos on Youtube or manuals explaining the process to rebuild and calibrate. I have no experience with your model of tester but you'll definitely need to change the caps and out of spec resistors before trying to calibrate. Keep us posted!
     
  15. Sg-ocaster

    Sg-ocaster Active Member

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    Yea I figured on a recap and clean up all switches test the resistors etc...
    It does come with a manual and roll chart. From what I'm reading online there are 3 resistors that may need to be adjusted to calibrate. I see a couple places that have calibration 6l6 tubes....on place gives a list of what they should read on a bunch of comm9n testers....not sure if the triplett 3413 is on the list tho....but I guess it's basically an eico 625 from what I hear.
    Now if FedEx will just get it hear.....its 50miles away now so hopefully tomorrow....but prolly Monday.
     
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  16. Sg-ocaster

    Sg-ocaster Active Member

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    Hey...good idea if I calibrate to test all my tubes at 200% I effectively double my tube stash:dude:
    Yea I hear ya on the b.s. eBay sellers.
     
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