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Do 12AU7 driver tubes make much of a difference?

Discussion in 'Amps and Cabs [BG]' started by i_got_a_mohawk, Jul 28, 2005.


  1. Do 12AU7 driver tubes make much of a difference?

    I was away to stick in an order for some new 12AX7's to replace the crappy ones that are in my amp right now, would it be worthwhile to replace the 12AU7's aswell, or do they not affect the sound as much?
     
  2. 8mmOD

    8mmOD

    Mar 20, 2005
    USA
    I endorse & use Tech 21 pedals, Eminence loaded cabs, EMG pickups, Jim Dunlop picks & Ernie Ball Strings, BC Rich Basses.
    What is in there now?
     
  3. Chef

    Chef Moderator Staff Member Supporting Member

    May 23, 2004
    Columbia MO
    Staff Reviewer; Bass Gear Magazine
    What amp, and what's stock would be useful info. What are you trying to achieve?
    I replaced the 12ax7's in my old fender bassman with 12au7's...they have a gain of about 70% less if I recall correctly. The bassman was too overdriven for me with the ax's in it. The au's made it much cleaner. YMMV, this trick did not work in my mesa 400+ to my satisfaction.
    12at7's split the difference more or less...there are guys here way smarter than me about this.
     
  4. 8mmOD

    8mmOD

    Mar 20, 2005
    USA
    I endorse & use Tech 21 pedals, Eminence loaded cabs, EMG pickups, Jim Dunlop picks & Ernie Ball Strings, BC Rich Basses.
    Chef-

    He has a Ampeg SVT-II (non-pro). I don't think he is asking about the gain difference, but instead the tonal diffence between tube brands... IOW, I don't think he wants to swap out 12AU7 tubes for 12AX7's. I think because he is planning to change the 12AX7's to a better quality, he wants to know if changing the brand of 12AU7's will make the amp sound even better (than changing "just" the 12AX7).

    Am I close i_got_a_mohawk, or are you just saying all the tubes are shot?
     
  5. your right, i want to change it tonally, i started a thread a while back on this

    it has three 12ax7's in the pre, and two 12au7's and one 12ax7 in the driver section

    the 12ax7's are all "national" made in china, and the 12au7's have an ampeg like logo on them, i am definatly changing the 12ax7's i was just wondering if id be aswell changing out the 12au7's too
     
  6. Sparkie

    Sparkie

    Nov 15, 2004
    It's my experience that the Chinese tubes are generally noisier and don't last as long be it from micophonic's, etc. I don't see much mention of 12AT7's which are used in guitar amps to tame gain/drive in the pre-amp section about 20%. It's the first tube of the series, (ususally located closest to the jack plug and farthest away from the power tubes), that effects your tone most. The rest more or less act as fill except for the last one, or the one closest to the power tubes. That's your phase inverter tube and does the most work as it gets constant current in a push pull fashion to manipulate the speaker. The PI tube should be replace as often as your power tubes.

    I like Electro Harmonix(Sovtek) for tone, consisancy and long life. With you amp on, instrument plugged it and volume on loud enough to hear it tap (lighty) your glowing tubes with a chop stick to determine if they are microphonic, loose or have an audio report. They shouldn't but if they do replace them. It's also a good idea to have spares in your grip just in case.

    Cheers
     
  7. I know the chinese ones are crap, thats why im replacing them, im getting either Electro Harmonix 12AX7 EH's or 12AX7 EH Golds

    Im not planning on using different types of tubes, im sticking to whats printed on the chassis :)
     
  8. 8mmOD

    8mmOD

    Mar 20, 2005
    USA
    I endorse & use Tech 21 pedals, Eminence loaded cabs, EMG pickups, Jim Dunlop picks & Ernie Ball Strings, BC Rich Basses.
    In that case, if you have never replaced the preamp tubes, I would just replace them all. The Electro Harmonix 12AX7EH & 12AU7 are inexpensive and I think they sound good... thats what I used in my SVP CL after trying several other types.
     
  9. cool, yeah, thats what i was thinking aswell, i was actually recommended the EH tubes by tube depot
     
  10. 8mmOD

    8mmOD

    Mar 20, 2005
    USA
    I endorse & use Tech 21 pedals, Eminence loaded cabs, EMG pickups, Jim Dunlop picks & Ernie Ball Strings, BC Rich Basses.
    Me too. at $7.95 they are a steal IMO
     
  11. yeah, but i bet they dont charge you $30 for the postage (damned UK)

    altho, it still works out to be about the same / bit cheaper than buying over here . . . :-/
     
  12. Ok, so what would you all says better, i have 2 choices here

    the JJ 12AU7 or the EH 12AU7, there's about £1.50 difference between the EH and JJ (JJ being more expensive)

    which is better, or is it neglegable at that price?
     
  13. 8mmOD

    8mmOD

    Mar 20, 2005
    USA
    I endorse & use Tech 21 pedals, Eminence loaded cabs, EMG pickups, Jim Dunlop picks & Ernie Ball Strings, BC Rich Basses.
    I'd email Christian about that. Its actually $1 (US) cheaper for the JJ at tubedepot.

    http://www.tubedepot.com/jj-ecc82.html
    http://www.tubedepot.com/eh-12au7.html
     
  14. ah right, i was looking at the hotrox site actually and just assumed it would be the same
     
  15. BurningSkies

    BurningSkies CRAZY BALDHEAD

    Feb 20, 2005
    Seweracuse, NY
    Having used both the EH and the JJ, I prefer the JJ.


    Email Bob at Eurotubes, and tell him what amp you have and what you're going for tonewise, and he'll send tubes to suit.


    I bet he won't rape you on the shipping either.
     
  16. what im looking for tonewise? he only seems to deal with JJ tubes!
     
  17. BurningSkies

    BurningSkies CRAZY BALDHEAD

    Feb 20, 2005
    Seweracuse, NY
    Yes. Bob only does sell JJ's. In fact, he's the US distributor.

    Yes again, if you tell him what kind of amp, what kind of music you play, and what your goals are tonally with your new tubes, he can pick ones for you.

    A co-worker of mine got one of his 're-tube' kits, and by explaining what he wanted to hear, Bob not only picked tubes, but told him which tube to put in which location in the amp.

    When I did new pre-amp tubes for my 400+, I talked to Bob about the fact that I need clean big lows without mud, and that's just what I got...and they were lots better than the stock Mesa tubes.

    The JJ's had good low end that was rich and smooth, but also had better overall useable tone in the mids and highs. The overall volume was higher too along with decent dynamics.

    I compared his high-gain 12AX7 to an EH12AX7, several Ei 12AX7's (both grey plate and silverplate), along with a NOS RCA, a Sylvania and a GE...and ended up liking the JJ. I do this with the tube section of my 3500 (just 1 12AX7) to hear the 'color' of the tube, and I also check it with my 65 VibroChamp guitar amp and a tele so I can hear how its tonal characteristics work in different settings.
     
  18. cool, i might just be being retarded, but there are no prices on the site, down to individual quotes is it ?
     
  19. 8mmOD

    8mmOD

    Mar 20, 2005
    USA
    I endorse & use Tech 21 pedals, Eminence loaded cabs, EMG pickups, Jim Dunlop picks & Ernie Ball Strings, BC Rich Basses.
    i_got_a_mohawk-

    If Tennessee to Scotland is $30 via Fed Ex (www.tubedepot.com), I am curious to see what the cost is from Oregon to Scotland (eurotubes.com). You should email Bob & ask.... well for me, becuase I am curious & I don't know your postal code :D
     
  20. BurningSkies

    BurningSkies CRAZY BALDHEAD

    Feb 20, 2005
    Seweracuse, NY