Got a vintage 12AX7... Now what?

Discussion in 'Glowing Bottle Tube Amp Forum' started by 50ShadesofOrange, May 22, 2020.

  1. 50ShadesofOrange

    50ShadesofOrange Tele-Meister

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    You’ve pretty much nailed it. The difference was pretty minor, and my ear isn’t refined enough to pick up very subtle differences.

    When I got it, I had a tech who is one of *the* guys for amp work in Dallas/Ft. Worth (although they’re a dying breed, so the competition is scarce) give it a run-through. He went with JJs on the preamp, trem and power tubes, and a Tube Amp Doctor one for the rectifier. His rationale was having had good experience with those brands for those applications, rather than running up the tab experimenting with vintage tubes.

    He has it sounding great, and being an expert, both with the technical aspects and an ear for this stuff, I suspect he got it darn near good enough for a hack like me.
     
  2. 50ShadesofOrange

    50ShadesofOrange Tele-Meister

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    Alright. I got to A/B the Mazda with the JJ.

    Two impressions, based on the same amp and guitar settings. The guitar was a Tele with Van Zandt True Vintage pickups, so pretty low output.

    1) While it may be confirmation bias, the Mazda sounds a little more 3-dimensional and fuller. The JJ sounds good, don’t get me wrong, but the Mazda is a little richer, more complex.

    2) This one’s easily observed/confirmed. I have more clean headroom with the Mazda. With the JJ, the stock Oxford started farting out when I strummed power chords on the dimed bridge pickup with the amp volume on 6. With the Mazda, it wasn’t until about 8.

    I think the Mazda will stay put in the Vibro Champ for now.


    Thank you all again for keeping me company along the way.

    Stay safe!
     
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  3. schmee

    schmee Doctor of Teleocity Silver Supporter

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    Soo.... do you sound like Stevie Ray now?
     
  4. 50ShadesofOrange

    50ShadesofOrange Tele-Meister

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    No, but I’m *really* close.

    I think I’m just a bone nut, custom compensated bridge, and new wiring harness with paper in oil caps away from being there.
     
  5. schmee

    schmee Doctor of Teleocity Silver Supporter

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    :lol:
     
  6. 3-Chord-Genius

    3-Chord-Genius Poster Extraordinaire

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    "5% to 18% improvement in tone"
    "Sounds more 3D"
    "Richer, more complex"

    I've hit the gold mine clicking on this thread!
     
    Si G X, Commodore 64 and radiocaster like this.
  7. radiocaster

    radiocaster Poster Extraordinaire

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    I have a 12AU7 from a somewhat sought after European maker (not that any 12AU7s are particularly valuable) from the 70s or 80s. Compared it to a JJ in an amp, and liked the JJ more.
     
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  8. 50ShadesofOrange

    50ShadesofOrange Tele-Meister

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    At the end of this little excursion into the world of vintage tubes, while this one worked out on the whole, I’m not sure (for me, at least) the vintage juice is worth the squeeze.

    Having a few days to reflect, I suspect new production tubes will be the way forward for me.

    The JJ sounded fine. And at a fraction of the price for NOS/ANOS, the current production tubes generally work, with a greatly-reduced risk of a dud or misrepresented tube.
     
  9. Commodore 64

    Commodore 64 Friend of Leo's

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    Within my circle/scope/span of influence, I find that old 12ax7 are pretty rare. When friends/family/re-store give me collections of old tubes it's almost always a collection from someone who has passed on, or something someone found in an antique mall or rummage sale.

    It's usually from an old TV repair person. I wonder how many of us can relate:

    1. You get a collection of pentode/triode 9-pinners, 6GHB8, 6U8A, 6EA8. Those can be fun. I have so many that I'll never use them all, but funt o build a pentode/triode preamp with those.
    2. A handful of 6V6, A couple handfulls of 6K6. TVs musta used these from time to time for sound. I have more of these than I'll ever use.
    3. A fair amount of 5Y3 and maybe a few other assorted rectifiers, 5U4 and 5V4. I'll never need to buy one of those new (or NOS).
    4. Beautiful Pristine Sylvania/GE/RCa box containing a dirty, clearly used tube of a different brand inside it. Those repair folks never could throw out a tube.
    5. Every once in a while a tube that appears to be pretty pristine and might have never been used, in an appropriate box. No way to tell really. But if one was unscrupulous, they might put it up on Ebay and say NOS/ANOS. Seriously...WTF is ANOS?
    6. At least once a year, a tube tester that tests for emissions? or shorts at low voltages. With a cylinder of crinkled and brittle paper that is no longer attached that would tell you the settings to use for each tube to test it.
    7. A WHOLE bunch of tubes that don't use 5,6 or 12 volt heaters.
    8. A load of Compactron tubes. Some have 3 triodes in them. Or 2 triodes and a pentode. I know someone who built a 1 tube amp, kinda cool.

    Anyhoo, I have a couple of amp mules (practice amps I roll tubes in). Simple push-pull octal power with a pair of 12AX7 or a pentode/triode and a 12ax7. I just stick tubes in there, and if they sound good and aren't microphonic, and work, then I prolly leave em in for a while. And I look like a badass because I have RCA/GE whatever tubes in my amps for all to see (in my practice amps in my living room).

    Caveat: Don't go throwing those tubes in your caddy that you take to gigs for backup. You'll end up replacing a bad tube with a bad tube and pulling your hair out. I really gave up on using anything but new production tubes on gigging amps. Suffice to say, I won't pay for a NOS tube. I might pay a pittance for a big basketful of questionable tubes and scavenge a dozen or so if I'm lucky.
     
    Last edited: May 28, 2020 at 11:19 AM
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  10. jackleg

    jackleg Tele-Meister

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    i have many nib 12ax7s from the sixties.. i guess i should be looking for a good used tube tester that won't break the bank.... any suggestions, brand, model, price??? thanks
     
  11. corliss1

    corliss1 Friend of Leo's Platinum Supporter

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    @jackleg - putting them in an amp is the best tube tester there is.
     
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