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12ax7 Tube Geeks

Discussion in 'Amps and Cabs [BG]' started by The Golden Boy, Aug 17, 2007.

  1. What would be the most "sterile," "transparent," "not warm," "hi-fi," sounding 12ax7s around? I'm not concerned about NOS or anything- I'm thinking about getting a very "immediate," Solid State sort of sound.

    I've got a Mesa Boogie Bass 400+ that needs tubes. I really like the SS bass amp sound, and a cross between the SS and tube sound is appealing.
  2. Tung Sol - new Sensor Corp. production
  3. edbass


    Nov 8, 2004
    Transparent, Hi-Fi 12AX7's, particularly with a tube output stage;
    Telefunken - very musical, somewhat available, nice pre amp tube.
    50's Amperex Script Logo (nearly unfindable) or Bugel Boy(still around) - clean, hi-fi, a little "gainy", but very sweet.
    Mullards don't suck either.
    All old and expensive, IMO nothing modern even comes close.

    But, consider 12AXT's or even 12AU7's to get away from voltage gain (potential harmonic distortion, or "warmth") in a "sterile" application. Also more reasonable because the guitar folks are mostly looking for '7's.
  4. Yeah, that's what I was thinking about- more "home stereo," less "plexi sag."

    I know there's different nomenclatures for the different tubes with different voltages and gain structures, I just don't know what they are.

    I do know the Mullards I have in my guitar amps are not the tubes I want in the Mesa.
  5. luknfur


    Jan 14, 2004
    Thing about the same pre tubes is they'll sound different in different gear.

    I'm guessing the tubes in the amp currently haven't been satisfactory or you'd simply replace them with the same tubes.
  6. DaveMcLain


    Jun 19, 2005
    Cuba MO
    Try that Mullard reissue that Groove Tubes sells, those sound good and give a bright sound. Also, old RCA 7025's like Fender used in the '60's and '70's are not too tough to find and might give the sound you want. You might have to try a couple to be sure you have a good one but they will last for years.
  7. Respectfully with all those saying "Mullard" or "mullard reissue". Mullards are phenomenal, spendy tubes - fabulous if you're looking for a classic, tube sound with sweet midrange. However, they are anything BUT hi-fi and/or even up and down the frequency range.

    Perhaps I'm mistaking the intent of the OP, but he seems to be asking for a "hi-fi" even rf response tube. I've played through everything mentioned so far in this thread, and the new Tung Sol 12AX7 is easily the cleanest and most hi-fi tube of the bunch. That's not always a good thing. If you're looking for sweet, smooth midrange and a bit of high-end rolloff with "traditional" tube character, the Tung Sol is probably not your best choice. It is, however, exceptionally even in response up and down the freq spectrum.

  8. scotch

    scotch It's not rocket science! Supporting Member

    Nov 12, 2006
    Albany, NY USA
    Please see Profile for Endorsement disclosures
    +1 to the old RCA 7025's.
    I think it's the most "neutral" sounding preamp tube I've tested. The volume may drop slightly, however as the gain isn't as high as the modern 12ax7's.
  9. lo-freq

    lo-freq aka UFO

    Jan 19, 2003
    DFW, Texas
    If you can find one, you might want to try a Matsush!ta 12ax7.

    I compared several tubes in a Demeter VTBP-201S and the Matsush!ta was the quickest, tightest, and most articulate.

    It did make the Dem sound just a bit thinner and I ended up replacing it with a JAN-Philips 12AX7WA which had a fuller, richer tone with better bass response.


    Thinking back, I'm wondering if the Matsush!ta might have worked better for me overall if I'd just bumped the bass boost up to compensate for the thinness.

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