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Recommend me a active preamp for my bass

Discussion in 'Pickups & Electronics [BG]' started by Melvin7822, May 20, 2004.


  1. Melvin7822

    Melvin7822 Supporting Member

    May 11, 2004
    Broomfield, CO
    I have a Fender fretless with an EMG J-set, but I want a lot more tonal variety. Can anyone suggest a good active preamp?
     
  2. sheepdog

    sheepdog

    Feb 20, 2003
    Birmingham, AL

    are your EMG Js active (require a battery)? If so, you might try adding the BTC preamp from EMG (bass and treble cut/boost). A regular preamp (aguilar, bartolini) would not work with your pickups unless the pickups were passive (no battery)


    forgive me if my answers seemed to assume a lower level of knowledge than what you have. Wasn't sure what point you were coming from....
     
  3. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    sheepdog gave a good recommendation regarding trying out EMG.

    there's plenty of good active preamps out there, such as:
    bartolini, seymour duncan, u/j-retro, aguilar, demeter etc.

    could you give more info about what you're looking for?
    i.e. 2 vs 3 band
    if 3 band, fixed mid freq (what freq?) or sweepable mids?
    are you willing to have routing work done if required? (different preamps are different sizes, and the standard front jack j cavity can be tight)
     
  4. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    sheepdog, this isn't the case. The preamps you mention will work with active pickups. The battery red lead for the preamp would need to be spliced in with the pickup battery wires. Some preamps may need 18v to operate effectively with both preamps and pickups powered off the same source. It may work at 9v, but distort easily when bass/mid boosted beyond certain amounts.

    There is one thing to look out for though: In the case of some prewired preamps (i.e. the bartolini harnesses), there would be a need to use different impedance vol and blend pots as the standard ones they use are suited to passive pickups (250k,500K) rather than 25K that EMG uses.
     
  5. sheepdog

    sheepdog

    Feb 20, 2003
    Birmingham, AL
    thanks for the clarification. I assumed the pickup output would be too high for the input stage of the preamp. Does your method bypass the internal preamp of the pickups? I don't follow what you mean...

     
  6. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    No, no bypassing done at all. I'm just outlining how you would run active pickups and preamp off of one battery - however, as I said, you'll get more headroom at 18v (assuming the preamp takes 18v, always check first).
    Apart from that, it's just normal wiring - pickup hot output goes to preamp input, blend pot, master volume, whatever.
     
  7. Melvin7822

    Melvin7822 Supporting Member

    May 11, 2004
    Broomfield, CO
    My EMGs are active. I don't care about any routing that has to be done. I'd prefer 3-band EQ, but I don't think I can fit that all in with only three knob spots, even with concentric pots (for an EMG preamp).
     
  8. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    have you seen the j retro? http://www.j-retro.co.uk - drop in jazz bass preamp, minimal soldering required. 3 band preamp, 3 stacked knobs.

    It does add a slight coloration by default, even with eq controls flat. But it's the most flexible commercially available onboard preamp out there.

    Steve Barr is the US distributor - http://www.vintagebass.com
     
  9. Melvin7822

    Melvin7822 Supporting Member

    May 11, 2004
    Broomfield, CO
    Yeah, I've been aware of the J-retro. I don't like that the bass and treble controls have no cut.
     
  10. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    the j-retro has cut on the treble. It's only the bass that is boost only.

    Are you thinking of the aguilar obp-1, which only has bass/treble boost?

    My personal favorite preamp is the aguilar obp-3, but you'd almost certainly need routing work done for that - maybe even taking the jack out the side instead of the front of the bass.
     
  11. sheepdog

    sheepdog

    Feb 20, 2003
    Birmingham, AL
    is the hotter output of the active pickups not too much for the input stage of the preamp?
     
  12. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    no. There are many basses with active pickups and active preamps - Warwick Thumb and Streamer being two examples.
    I personally have run active pickups with aguilar, bartolini and u-retro preamps.

    Just curious why you're so sure this would be an issue?
     
  13. sheepdog

    sheepdog

    Feb 20, 2003
    Birmingham, AL

    just from other stereo/electronics experience. I assumed the higher output of the active would cause the preamp to clip from too much signal at the input. Maybe it doesn't apply to bass wiring.


    also, if the pickup signal is already boosted (active), what does the preamp do (not the eq section, the actual preamp)? Does is boost the signal further?
     
  14. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    It can do. Bart preamps and u-retros have an adjustable input gain level. Aguilar preamps are zero gain when flat, obviously bass/mid boost etc will boost the signal.
     
  15. A9X

    A9X

    Dec 27, 2003
    Sinny, Oztraya
    Making the pickup active could mean that the designer has chosen a smaller number of turns in the coils and therefore a smaller signal, then used the integrated active section to boost the level to near that of a 'standard' passive, with the added advantage of a lower output impedance. I believe this is the case with many EMG designs and the Alembics. Probably others too.

    Depending upon the design of the following preamp stage (eg Jretro/Bart etc), the preamp will add a buffer after the variable impedances of the tone circuits (and consequently a lower output impedance), possibly add gain, and the active stages may be required as some tone designs cannot easily be implemented with simple passive designs, or not without compromises in performance in other areas, eg noise.

    I hope that made sense, if not I'll clarify.
     
  16. JOME77

    JOME77 Supporting Member

    Aug 18, 2002
    Georgia
    I agree. If you're limited to a 3 knob configuration, the J-Retro would be your best bet. It's not cheap though (made in UK). Maybe consider moving your output jack to the side of the body and adding another control. If you dont use the EMG 3-band, IMO the Demeter or Aguilar OBP-3 sound best with the EMG's.