Can anyone tell me if these are good tubes?

Discussion in 'Glowing Bottle Tube Amp Forum' started by PihaBeach, Aug 9, 2015.

  1. PihaBeach

    PihaBeach Tele-Meister

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    Sold as RCA 12ax7. Lot of 8 of them.
    I haven't received them yet, but I can see Wurlitzer written on some of the.
    I have a few amps that could do with pre amp,tube upgrades.
    I see some of these go on eBay for quite good money. How did I know if these are desirable tubes? ImageUploadedByTDPRI1439165263.900889.jpg
     
  2. SamClemons

    SamClemons Poster Extraordinaire

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    Excellent tubes
     
  3. PihaBeach

    PihaBeach Tele-Meister

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    Without knowing how they test, would you place an approx value on them??
    Just want to know where to bid too. I can use four of them and then sell the rest to cover costs.
     
  4. HotDan!

    HotDan! Friend of Leo's

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    Yes, some of the best and absolutely dependable...
     
  5. surfoverb

    surfoverb Doctor of Teleocity

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    ill take 2
     
  6. HotDan!

    HotDan! Friend of Leo's

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    See? Thereya go. Surf's got ya covered for two of 'em so get four and you got a free one...Maybe one set left over too...:D
     
  7. soulman969

    soulman969 Telefied Ad Free Member

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    Looks like a nice score if they all test out as good.
     
  8. PihaBeach

    PihaBeach Tele-Meister

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    Haha ok done!
    Hey your in Virginia? My better half is from there, Richmond. We go there every year.
     
  9. PihaBeach

    PihaBeach Tele-Meister

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    Excellent.
    Well I bid on em and picked up the lot for about $65 USD
     
  10. SamClemons

    SamClemons Poster Extraordinaire

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    You made a good deal at 65. A good pair would bring 40-60 dollars. I sell a lot of organ pulls and most of them check out good.
     
  11. PihaBeach

    PihaBeach Tele-Meister

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    Cool
    I suppose there is no easy way to get em tested.
    I wonder if my amp tech has a tester. Does it take long to test a tube?
     
  12. telex76

    telex76 Doctor of Teleocity Ad Free Member

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    As long as you know they aren't shorted, the best test is how they perform in your amp.
    I've got an old tube tester, about all it's good for is checking for shorts.

    If yours look okay with no signs that they have lost vacuum, and no rattles when you shake them, I wouldn't be afraid to try them in my amp.

    Some of my best old tubes are RCA organ pulls with Lowrey stamped on them.
     
  13. PihaBeach

    PihaBeach Tele-Meister

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    Great, thanks very much
     
  14. DaveKS

    DaveKS Friend of Leo's

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    The bane of buying tubes like these on eBay are 1. microphonics and 2. being noisy and hissy.

    Don't be surprised if you have to get a refund or if no guarantee taking the loss on 2-4 of them. Bulk deals like this and that's a very good deal you got, you will almost always get some sub-par tubes. Most sellers like that, just run them in a tester for basic strength, they do no actual in amp testing for noise and microphonics.

    When you get them, run each one in a v1 slot of amp, preferably a high gain one that will reveal problems better. Be ready to switch amp off if it sounds like it's shorting or starts red plating. Then if seems ok turn vol up and listen for noise and then lightly tape tube with fingernail or chopstick etc, listen for tink sounds (really micro) or thumps (slightly micro) coming from speaker, if you hear those it's microphonic, may start howling like a banshee if it's really bad. If you get some, try to get a partial refund or if no guarantee you'll just have to eat the losses. Slightly micro tubes can be used in some v2,3 positions or PI slots. If their really noisy/hissy, not much you you can do about that, eBay tubes are what they are, a roll of the dice.

    Been down this road many times and that's best advice I can give you.
     
  15. Singin' Dave

    Singin' Dave Friend of Leo's

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    $65 for that lot is a nice buy, and yes, a few of them may perform subpar, but odds are good you'll have some gems in there too.

    RCA 12AX7s are my go to V2 tube in my SF reverb amps. I use my '69 Vibrochamp to test 'em.

    Good luck!
     
  16. Wally

    Wally Telefied Ad Free Member

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    +1with both telex76 and Dave KS. Good luck with them.
     
  17. PihaBeach

    PihaBeach Tele-Meister

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    Thanks for the detailed info! Yes I. Sure I'll get a few bad eggs in there, but really I just need some for my Princeton reverb, champ and vox ac15.
    Which one of those amps would be best to test? Probably the ac15?
     
  18. PihaBeach

    PihaBeach Tele-Meister

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    Yeh hope I get some gems. I'll be using my ears to test em
    May even do a little sound test
     
  19. Johnny Cache

    Johnny Cache Former Member

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    The only way to really tell is to try them. Yet I would think they would be good, but saying that I would want to run them through my tube tester first to check them out.
     
  20. muchxs

    muchxs Doctor of Teleocity

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    Takes a second. Plug the tube into your amp. If it works and sounds good you got a good one. :D

    The bane of selling tubes on eBay are customers who pay eight bucks each for used RCAs and then think they have sumthin' to complain about. :rolleyes:

    I usually have a "line in the sand" price I'll pay. I don't overpay and I don't give anyone a rash for a crappy tube or two out of a big lot. After all... you're probably going to get a crappy tube or two when you buy new Chinese, Czech or Russian tubes.

    I drop the noisy ones off the porch roof when I'm testing 12AU7s. :D
     
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