OBP-3 and Ibanez SRC805

Discussion in 'Pickups & Electronics [BG]' started by Dudemonkguy, Jul 31, 2018.


  1. Dudemonkguy

    Dudemonkguy

    Jul 31, 2018
    The Ibanez factory wiring somehow utilizes the active treble control as a passive tone knob when the bass is set to passive mode. I've seen some wiring diagrams for the OBP-3 and have only encountered diagrams where the passive tone knob is a separate knob. Has anyone had experience wiring a single knob for two purposes like this?

    Edit: If it helps, The bass has 5 knobs, two switches. Active bass, mid, & treble. Passive/active switch, 3 freq mid eq (switching to 2 band with OBP), 1 volume, and pickup blend.
     
    Last edited: Jul 31, 2018
  2. Aloe

    Aloe

    Apr 10, 2016
    Ukraine
    I don't think that's possible with OBP3. it needs 50k pots, whereas for passive tone you most likely want 250k or 500k, but not 50k.

    you could go with a stacked pot to mount, say, active bass and treble in one hole and passive tone control in other one, so you don't need extra holes in your guitar.
     
    Last edited: Aug 1, 2018
  3. 4StringTheorist

    4StringTheorist Supporting Member

    Totally doable!

    Get a dual potentiometer with 50KΩ linear taper and 250KΩ audio taper sharing the same shaft.
    Get a 4pdt switch for the active-passive switch.

    50K linear is for the active treble wires
    205K audio is for the tone wires

    Wire one half of the 4pdt switch as a standard dpdt acitve passive switch.

    Use the other half of the 4pdt so that in active mode, the tone capacitor is open (ungrounded)

    This will mean that in active mode, that knob functions as the active treble EQ. In passive mode, it will fundtion as a passive tone knob.
     
    Dudemonkguy likes this.
  4. Crater

    Crater

    Oct 12, 2011
    Dallas, TX area
    It could be a plain old 250 K ohm pot and standard 0.05 microfarad capacitor before the preamp input.

    G&L L-2000s are wired this way, the treble and bass cut controls are passive and placed before the preamp in the circuit, so they work whether the preamp is in the circuit or not.
     
  5. Dudemonkguy

    Dudemonkguy

    Jul 31, 2018
    The Google is not yielding fruit for this specific pot. Do you have a source for these?
     
  6. 4StringTheorist

    4StringTheorist Supporting Member

    I remember that I've seen them in the past, but I don't know about them now. Check bestbassgear.com for the first spot. Then allparts or stewmac
     
  7. 4StringTheorist likes this.
  8. Dudemonkguy

    Dudemonkguy

    Jul 31, 2018
    Awesome! You guys have been a great help so far!
    Alright, ran into one problem that I'll need your help with though.
    So I installed everything, sounds good, works good, except for one thing.

    The volume knob is not sweeping the full range, it seems like it only runs from 75%-100% or something. I'm thinking this has to do with the taper or resistance of the pot. I've got the stock volume pot at 500k(Bartolini MK-1's). The pot says B500k on the label, no other markings so I'm unsure of whether its a linear or audio taper.

    This is my first "real" install of an active system in a bass. I installed a EMG kit in a Peavy Fury V about a year ago, and I think I soldered 3-4 connections for the whole shebang. This is a whole 'nother deal.
     
  9. Dudemonkguy

    Dudemonkguy

    Jul 31, 2018
    So, I am considering this as the wiring scheme. Unsure of whether the blue wire is in the correct spot, maybe in terminal C under where the volume hooks up?
     

    Attached Files:

  10. Dudemonkguy

    Dudemonkguy

    Jul 31, 2018
    This is probably the winner, mislabeled output wire on previous diagram
     

    Attached Files:

  11. Your second picture is the right one lol.

    Did you get the volume figured out?
     
  12. Dudemonkguy

    Dudemonkguy

    Jul 31, 2018
    Now everything is 100% with the 250k volume pot. I had to clip a tiny capacitor that was soldered onto the active treble/passive tone knob. It was there when the pot arrived in the mail, but was grounding the passive side of the tone knob so that the active treble cut/boost was not activating in active mode. Just a heads up.
     
  13. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
    May 16, 2022

Share This Page