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BBE T-MAX owners

Discussion in 'Amps and Cabs [BG]' started by ivanthetrble, Jan 9, 2005.


  1. ivanthetrble

    ivanthetrble

    Sep 9, 2002
    Orygun
    I have heard a couple of comments on the sensitivity of the gain control on the BBE T-MAX pre-amp. It seemed like the gain was very sensitive and easy to overdrive. I switched the 12AX7 tube out and put in a Phillips JAN 5751 (only about 70% of the gain of the 12AX7) and wow, big difference! The gain is much smoother and more managable. Much easer to set the gain when playing an 18v onboard pre-amp than with the 12AX7. Sounding very nice today thru a QSC PLX 3002 and a Bergantino HT210. Very nice indeed. :hyper:
     
  2. dunamis

    dunamis

    Aug 2, 2004
    Charlotte
    +1 on the JAN 5751.

    I replaced the 12AX7 in my tube compressor with a NOS 5751-- much improved response and a good deal quiter as well.
     
  3. Mobay45

    Mobay45 The artist formerly known as "Big Daddy"

    Apr 28, 2004
    Irving, TX
    Where's the best source to get tubes?
     
  4. Razor

    Razor

    Sep 22, 2002
    Dallas
    Lord Valve is good to get tubes from...do a search on here for him.
     
  5. lo-freq

    lo-freq aka UFO

    Jan 19, 2003
    The Republic of Texas
    There is also The Tube Store.
    Good reliable service.
     
  6. Mobay45

    Mobay45 The artist formerly known as "Big Daddy"

    Apr 28, 2004
    Irving, TX
    Thanks for the help guys. I know that "NOS" means new old stock, but what does "JAN" for? Also, do you know how the Sovtek tubes are?
     
  7. ivanthetrble

    ivanthetrble

    Sep 9, 2002
    Orygun
    IIRC, JAN stands for "joint Army/Navy". I think they were made for the military so there seems to be a lot of them available at a pretty good price. Lord Valve is a great source for tubes and advice as is The Tube Store and might also try googling "Electron-valve" to get another good source. I have another pre-amp that I want a bit more gain and the Sovtek 12AX7LPS are a very good choice for that situation.
     
  8. Mobay45

    Mobay45 The artist formerly known as "Big Daddy"

    Apr 28, 2004
    Irving, TX
    Got it. Thanks.
     
  9. OBBM

    OBBM

    Jan 26, 2005
    Surrey, UK
    I had a similar problem. 5-string Bongo with bass full up just overloaded. The gain knob could only just be off the end-stop. I got hold of a JAN5751, not easy in UK, but it didn't fix the problem. Several emails to BBE brought forth some mod details (component changes/removals). Interestingly the tube stage is almost identical to an Alembic FX2. I did the mods today and it is purring now like a kitten with the original Groove Tubes tube back in. I reckon BBE know about the overload problems with 18-volt basses but have done/said nothing.
     
  10. Kelly Lee

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

    Feb 17, 2004
    Marana, AZ, USA
    Another good place for tubes is Eurotubes.
     
  11. ivanthetrble

    ivanthetrble

    Sep 9, 2002
    Orygun
    So what kind of mods are we talking about here. Simple things? Do tell!
     
  12. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    i always thought JAN was short for january...........

    BTW, the b-max is IIRC based on the fender tone stack just like the alembic and trace v-type are. i belive the specific circuit was from the showman. IIRC, these were all circuits made available by RCA, (from what i hear in hopes that peopel would design things using them and then need to buy parts and tubes from ....RCA). I think that's also called the Tom Walker design. (maybe he was the cat that worked at rca that came up with it?) in any event, a great sounding circuit.
     
  13. OBBM

    OBBM

    Jan 26, 2005
    Surrey, UK
    Here you go, very straight forward

    R7 changes from a 46.4K resistor to a 68.1K
    R10 changes from a 46.4k resistor to a 21.5K
    Capacitor C8 and C9 are completely removed

    Worked for me. No more overload with Bongo or SR5.

    Just done a weeks tour with another band and their bass player used a Rickenbacker though it. Great sound and no problems. For the dates with no DI we used the Sonic Maximiser - Wicked.

    Happy soldering :D
     
  14. OBBM

    OBBM

    Jan 26, 2005
    Surrey, UK
    The problem was the 18-volt electrics of the Bongo was completely overloading the front end, especially if I had the bass control wound up on the Bongo. The gain control could not go above '1'. Now I can go higher. All I can say is carefully remove and change the components, or get a tech to do it, try as see if it works for you.

    I think that this sort of thing is very individual. Don't blame me if it doesn't work for you.