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active passive switch on my OBP-1

Discussion in 'Pickups & Electronics [BG]' started by turkish, Feb 23, 2003.

  1. turkish

    turkish Guest

    Jul 14, 2002
    FCCAUSA, or here
    i've got theis frankenstien bass which amazingly cost me about 350$ yes sounds fantastic, it's really amazing yet the playability is not very good, the sound offsets it though

    i'm rambling :D :D

    anyway it's got ultrajazzes in it an an aguilar OBP-1 preammp in it, i would very much like to put an active passive switch in it, is this possible? And if it is how would i go about doing it?
  2. ModulusAcacia

    ModulusAcacia Commercial User

    Mar 22, 2000
    Middletown/Cincy, OH WHO-DEY!
    owner: J. Kennedy Guitar Repair, Guitar tech for Walk the Moon
    check the aguilar website, they've got all the wiring diagrams you can handle for the OBP-1 and 3. I hope that helps :)

    Justin K.
  3. Nino Valenti

    Nino Valenti Supporting Member Commercial User

    Feb 2, 2001
    Staten Island NYC
    Builder: Valenti Basses
    <a href="http://www.aguilaramp.com/newsite/html/diagrams/diagramobp1.htm"><b>CLICK HERE</b></a> :bassist:
  4. It's possible with any and every preamp that does not have PCB-mount pots that would hinder modification. The OBP-1 is a box with wires sticking out of it, so you can certainly wire it in any fashion that you want.
  5. TinyE

    TinyE Supporting Member

    Jan 31, 2013
    revival of an old thread, but can someone please look over my design? i'm trying to do the same thing. 1 pickup, an obp-1, and i want a passive switch. i used the aguilar drawings, but really just want a second set of eyes.

    my drawing
    the originals

  6. 4065969204_ddf7d1c0e3_o.
  7. somebrains


    Feb 7, 2017
    Wiring a route from the pull to the output jack is cool.
    Taking the passive tone option from a Nordstrand wiring diagram would be cooler.
    I'll get around to that one day.
  8. TinyE

    TinyE Supporting Member

    Jan 31, 2013
    thanks for this one. it won't give me a passive tone control though. any way to wire that in? would i put it between the bottom left terminal and ground (with the cap)?

  9. Simply wire the tone control to the input of the volume pot, where the pickup connects.
  10. TinyE

    TinyE Supporting Member

    Jan 31, 2013
    Interesting. What would that pot do in active mode though being wired straight to the vol pot? I though by switching into active, I'd need to bypass the 250k tone pot, and use the 25k ones wired into the pre. Sorry, I'm a little behind on the guitar electronics!

  11. The tone control works exactly the same whether the preamp is in the circuit or not. If you don't want a tone control when the preamp is being used, then there us an alternate switching scheme that will accomodate it, but I have never seen the point in bypassing the tone control for active mode.

    The 25k pots are for the EQ only. Don't try to use a 25k volume or tone pot unless you don't want to be able to use it when the preamp is bypassed. 250k or 500k pots should be placed before the active/passive switch to avoid the drastic change in impedance that occurs otherwise.