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JJ's 12ax7 + Trace Elliot RAH350SMX = WOW!

Discussion in 'Amps and Cabs [BG]' started by Kelly Lee, Jul 23, 2005.


  1. Kelly Lee

    Kelly Lee Yeah, I'm a guy! Supporting Member

    Feb 17, 2004
    Marana, AZ, USA
    I just thought I would share my experience. I recently decided to try a JJ 12ax7 in my QuatraValve and thought "hmm, why not try it in my RAH350SMX head as well?" I have read so many places that a preamp tube swap on a hybrid head really doesn't make much of a difference.

    Well, I disagree when it comes to TE heads! WOW, what a difference one little tube can make! My tone became much thicker and more round. It also fattened up the bottom end alot. One other little side note, my already excellent sounding harmonics somehow sound even richer. Wow, what else can I say? :bassist:

    Any other Trace Elliot or other hybrid owners done a tube swap with noticeable improvements?
     
  2. fast slapper

    fast slapper

    Dec 11, 2001
    Fresno, CA
    What tube did you have in your RAH350SMX originally?

    I've been considering putting a JJ in my Hughes & Kettner.
    There's currently a TAD-12ax7 which I understand Trace used in many of their amps.
     
  3. Kelly Lee

    Kelly Lee Yeah, I'm a guy! Supporting Member

    Feb 17, 2004
    Marana, AZ, USA
    I don't really know what tube was in there. It has absolutely no markings on it. It looks just like the JJ I put in. Everything is identical except for the lack of markings and the obvious tone differences.

    Here is a pic of the JJ:
    [​IMG]
     
  4. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    Fremont, Ohio
    Editor-in-Chief, Bass Gear Magazine
    How did you like it in your Quatra Valve? I really think that the JJ is the best modern 12AX7 out there. In many ways, it reminds me of my NOS Telefunkens. Great tube. I still am trying to find the time to go through all my NOS tubes and pick the ideal set for my V8 and Quatra Valve, but you can do a lot worse than just going with all JJ's let me tell you what!

    Tom.
     
  5. BurningSkies

    BurningSkies CRAZY BALDHEAD

    Feb 20, 2005
    Seweracuse, NY
    I put 4 new JJ's in my Mesa 400+ and it definitely made a big difference. Bob @ Eurotubes will 'pick' tubes to match your tonal goals too...a nice service to have when people these days don't know so much about tubes.

    He tells me that the biggest difference will be when he gets his hands on the power section of my 400+.
     
  6. jgsbass

    jgsbass

    May 28, 2003
    Floral Park, NY
    I put 12ax7's from a 1960's stereo into a SWR 350x and aPresonus TubePre preamp. There was a noticable difference in both units although the preamp had more of a difference. The tubes were Telefunkens, manufactured for Harmon Kardon. They had less than 50 hours of use ( maybe less: my parents hi-fi system) and were dormant for 30 years. I have the feeling that tubes, like basses, have their own mojo, and it differs a little from tube to tube, even with identical make and manufacture.
     
  7. Chef

    Chef Moderator Staff Member Supporting Member

    May 23, 2004
    Columbia MO
    Staff Reviewer; Bass Gear Magazine
    I want to echo Burning Skies comments about Bob at Eurotubes. I've worked with him a couple of times now. He wnet waaay out of his way to help me thru my last project. He's an exemplary vendor, and I will do biz with him again in the future.
    I may have to buy a few more jj 12ax7's to play with in a couple swr/eden this's and that's I have laying around....

    It's 110 dregees here today.
    Playing with tubes in the basement sounds like a really good idea;)
     
  8. 43% burnt

    43% burnt an actor who wants to run the whole show

    May 4, 2004
    Bridgeport, CT
    Cool, I'm gonna try this with my trace too. I've also heard nothin but good stuff about JJ tesla's. Is there any biasing that needs to be done, or Can I just pop a new one in my AH250?
     
  9. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    Fremont, Ohio
    Editor-in-Chief, Bass Gear Magazine
    You don't need to bias preamp tubes. As long as it is the same tube type, you should be plug and play friendly! Some preamps will even allow you to try different tubes with the same pinouts (like 12AX7, 12AU7, 12AT7), but inquire as to this compatibility before you do.
     
  10. Kelly Lee

    Kelly Lee Yeah, I'm a guy! Supporting Member

    Feb 17, 2004
    Marana, AZ, USA
    Tom, I actually haven't tried it in the Quatra yet. It sounds so good in my SMX I don't want to pull it out! :p Ah, I'll probably try it out after band practice tomorrow. I'll post back when I do.
     
  11. RevGroove

    RevGroove Commercial User

    Jul 21, 2002
    Burlington ON Canada
    Manager, Account Services: Long & McQuade Ltd. (Burlington); MTD Kingston Basses International Emerging Artist; Bartolini Electronics Emerging Artist
    Where the heck did you read that??? Believe me, mys XS800H sounded great with the stock Sovtek 12AX7, but putting in a Groove Tubes ECC83S in it's place I got very similar results to yours.

    From the info page for GT ECC83s: GT-ECC83-S
    (European, very linear, or true, tone...might be best bet for bass). The standard tube of Marshall and Vox amps.


    I agree, the ECC83S might just be..."best bet for bass!"
     
  12. tornadobass

    tornadobass Supporting Member

    Nov 20, 2000
    Iowa City, Iowa
    Endorsing Artist: Black Diamond & SuperSensitive strings
    This is my favorite tube for my SWR SM-400 and SM-400S! Glad to hear they're gaining in popularity. The short plates (is that the right term??) in this design make it easy to ID. Amost every other tube I've seen has longer plates.

    On the SWR amps, the tube makes a difference. OTOH, different tubes on the Eden WT-300 I owned for awhile made no difference.
     
  13. jobu3

    jobu3 Artist formerly known as Big Joe

    Feb 17, 2002
    Mountain Top, PA
    I swapped out tubes in three different SWR heads... In the Chrome 350 (not 350X) I had, it made no difference at all what I put in there.

    In the SM-400S and the older, red-faced 350 it did make a difference. More so in the 400S.

    Noticeable differences were also noted in a couple of Hartkes (a 3500 and a 7000). The biggest difference I noted in preamp tube swapping came with an Ampeg SVP-Pro I had. Tubes used were NOS Chinese in the SVP, and assorted Svetlana, JJ's, and GT's I've had laying around...
     
  14. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    Fremont, Ohio
    Editor-in-Chief, Bass Gear Magazine
    Of all the gear that I have tried swapping tubes in, I heard the least difference from my Eden Navigator. I think it has to do with the way that Eden incorporates the tube into their preamp layout.

    Tom.
     
  15. DEVILMAN

    DEVILMAN

    Nov 24, 2001
    New York,NY
    +1

    ~S~
     
  16. these are going pretty cheap on ebay. i may have to pick one up!

    are there specific types of these? or are the JJ 12AX7's all the same? (i.e. MIA, MIM etc?) :)
     
  17. Kelly Lee

    Kelly Lee Yeah, I'm a guy! Supporting Member

    Feb 17, 2004
    Marana, AZ, USA
    I think they are actually all the same but I too recommend Bob at Eurotubes. He has been very helpful and has put up with my many e-mails.

    He is selling the standard tube for $8 and he has the high gain version version for $10. They are the same tube its just that he test them for output to make make sure they gain is really good. Check him out.