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Genz benz shuttle 6.0 tube replacement

Discussion in 'Amps and Cabs [BG]' started by rockinpop, Mar 12, 2009.


  1. rockinpop

    rockinpop Gold Supporting Member

    Feb 21, 2008
    Lindenhurst, New York
    Does anyone out there know how to replace the 12ax7 tube in the shuttle 6.0? I just want to be sure before I start unscrewing things. Thanks!!:bassist:
     
  2. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    When removing the tube retainer (a substantial component), be sure to hold the hex standoff before unscrewing the retainer screw. Support the tube socket when removing and installing the new tube. Do all of this with the unit unplugged from the power source (of course).
     
  3. Marley's Ghost

    Marley's Ghost Gold Supporting Member

    Feb 9, 2002
    Tampa, FL
    I'm in. What tube are you using?
     
  4. Michael Vee

    Michael Vee Supporting Member

    Feb 3, 2004
    Knoxville, TN
    Replacing the Shuttle tube was discussed at some length in another thread.

    The tube I used is a 1999 Sovtek 12AX7LPS. The improvement was quite audible to my ears.

    Removing the factory tube is easy if you follow Agedhorse's instructions. You do need to support the board the tube socket is mounted on and go easy on twisting the tube to loosen the pins in the socket. Don't force it.
     
  5. Marley's Ghost

    Marley's Ghost Gold Supporting Member

    Feb 9, 2002
    Tampa, FL
    MV, do you think there is a big difference between the NOS and new Sovtek? Having a hard time finding a NOS.
     
  6. WRBass

    WRBass

    Dec 10, 2006
    Houston, Tx.
    I recently purchased a Shuttle 6 from another TB'er and so far, I love this amp and the tone I get from it. But, I ordered some replacement tubes to experiment with to see if changing them would make any difference in tone. I ordered a Sovtek 12AX7LPS and a JJ ECC83/12AX7.

    Just to make sure I wasn't subconsciously influencing the testing, I recorded a short line on a looper so each test would have an indentical input. I recorded each test on the PC using the DI out on the Shuttle into a Line 6 USB adapter.

    Maybe it's just me, but I can't hear any differences!

    Ruby 12AX7
    JJ ECC83 12AX7
    Sovtek 12AX7LPS

    I had the gain and volume on max and the Input O/L was just barely coming on for each tube.
     
  7. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    I can't tell a difference, either. I usually can't. But I like to use NOS tubes just because I think they're made better. Sonically, I think the differences between tubes are highly overrated. Subtle shading at best is what I hear with tube changes. Other people report the differences like they're night and day, so maybe my hearing's shot.
     
  8. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    By design, the preamp circuit topology does not emphesize the possibly radical deviations in the various parameters that tubes can exhibit due to manufacturing and materials tolerances. The main reason we chose this topology (other than the desireable overload characteristics) is because it's important do be able to deliver a consistent product, one without a lot of variation. Otherwise for each (potentially outstanding sounding) tube some customers would end up with some pretty mediocre performance which is really unfair considering we have control over at least a lot of this variance. My job as an engineer is to deliver the best (tube) sound quality to the largest number of our customers. We want to be sure that the amp sounds as good as possible without customers getting stuck, even with average tubes. So the tradeoff is a more even performance across a large tube sample at the tradeoff of perhaps a 1 in 500 tube not sounding as good as it might otherwise.

    Hope this helps.
     
  9. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Very interesting, Andy. Thx for the explanation. BTW, other than a little excess noise that didn't sound like it came from the amp, I thought those clips sounded pretty excellent.
     
  10. Yeah I found this too.
     
  11. Skeletomania

    Skeletomania

    Oct 25, 2005
    hong kong
    Call me crazy, but I did hear the difference. I'm not sure if you've changed anything, but the difference between the Ruby and the Sovtek is quite audible.
     
  12. Marley's Ghost

    Marley's Ghost Gold Supporting Member

    Feb 9, 2002
    Tampa, FL
    Well, I ordered an 01 NOS Sovtek on Evil Bay. I am doing some recording on my own so I should have some samples to compare when it comes in next week.
     
  13. Medford Bassman

    Medford Bassman Supporting Member

    Aug 8, 2007
    Medford, Wisconsin
    Frankly, I'm not that smart to be opening up amps and replacing parts. PLus, I use the 6.0 for alot of gigs and I just plain like how it delivers.
     
    theduke1 likes this.
  14. WRBass

    WRBass

    Dec 10, 2006
    Houston, Tx.
    The noise is being created by the Boss Loop Station. But, I only hear it through the DI and computer which is recording it. I'm pretty sure that I eliminated the amp from causing this.
     
  15. georgestrings

    georgestrings Banned

    Nov 5, 2005


    Would you say the same thing applies to the NeoPak 3.5, Andy???



    - georgestrings
     
  16. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Are you running the loop station in front of the amp or in the effects loop? If you run in front ofthe amp, you can use the pre DI out but if you run in the loop you must use the DI in post position.

    In general, the tradeoff will be that there's more noise if you run in front of the amp, but this may or may not be noticeable depending on the device.
     
  17. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Yes, pretty much.

    While I have designed tube based preamps for many years, I have noticed that some tube parameters vary an awful lot and I decided long ago that we (and our customers) are better off getting 95% of the "tone" out of 100% of the tubes than a few customers getting 100% of the tone out of those few special tubes but the remaining customers getting only 70% of the tone they paid for. It's a tradeoff that seems odd, but none of us have any control over the consistency of the tubes that are on the market. Even NOS and vintage tubes vary wildly. I have a box of about 50 vintage 12AX7's that I use for comparison testing (going back to WW-II era) and a lot of careful consideration has gone into this.

    Also, this design is important for controlling microphonics which is an especially important consideration in a bass combo amp. Microphonics can cause additional non-musical artifacts (ghost notes, blurring and wierd harmonics) that take away from the fundamental sound of the amp. It can also destroy the punch and attack.
     
  18. georgestrings

    georgestrings Banned

    Nov 5, 2005

    Thanks for the explaination, Andy - now knowing this, I won't bother buying a few different tubes in search of the "best sounding" one... Anyways, I really liked the sound of my NeoPak with the original tube in it...



    - georgestrings
     
  19. WRBass

    WRBass

    Dec 10, 2006
    Houston, Tx.
    For this test I was running it before the amp because I wanted to make sure it was going through the tube. And, I was using post DI. I'm pretty sure that it's not the amp and that it's related to the looper or the computer.
     
  20. Your not crazy...

    It is pretty darn close but I hear slight differences too... I could only descibe it as the Ruby sounds a little more warm and less defined (toobie sounding), while the Sovtek has more of a cleaner, percussive vibe. The other one falls in between closer to the Sovtek.

    It sure is not going to make much of difference on a loud stage or most recording situations.

    I have to check this amp out...
     

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