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Love the passive pickups, hate the preamp- new to DIY

Discussion in 'Pickups & Electronics [BG]' started by CM63, Apr 23, 2019.

  1. CM63


    Feb 9, 2013
    Walnut Creek, Ca
    My Spector legend bass came stock with Bart P/J pickups and an active Tone Pump (with no trim pots), I want to convert it to passive only.
    Too broke to take it to a pro.
    If you have done so, how have you 'home" converted your active bass to passive?
  2. https://www.seymourduncan.com/wp-content/uploads/2016/05/P_JBass_Standard.pdf

    If you want it a little brighter, use 500k Ohm pots.

    If you want to fill the 4th control hole, consider adding a bass-cut pot like in this drawing:


    The bass-cut pot uses a reverse-audio taper at 1 MegOhm & a 2.2 nanoFarad capacitor.

    For the treble-cut pot, if you want it a little muddy when you roll it all the way back, get a 47 nanoFarad cap, otherwise get a 22 nF cap.
  3. CM63


    Feb 9, 2013
    Walnut Creek, Ca
    Thanks! Sounds like a great option!
  4. blujosh


    Dec 8, 2009
    San Fran
    @Killed_by_Death , thank you for sharing this info. i had the same question (to convert another PJ bass with vol, vol, active-tone controls) and then found this post. when you say "If you want it a little brighter, use 500k Ohm pots" were you referring to the volume pots, the tone pot or both? wasn't sure how the higher value affects each control. thanks again!
  5. fermata


    Nov 10, 2015
    Mountain West
    1M Ohm reverse audio taper pots can be a bit hard to find; I think G&L sells them.

    Another cool passive control is the Bill Lawrence (Wilde Pickups) Q-filter (like on a Gibson Ripper). That would be my choice if you need an extra control.

    For pots, you can use 500K for volume and tone. I prefer 250K for tone; nothing happens for the first bit of the 500K pot’s rotation, which bunches the treble cut into a smaller range of rotation. Volume and tone don’t have to be the same value. Regardless, make sure you use an audio taper pot for tone. Volume can be audio or linear taper. (For dual volume circuits, linear taper gives more control over pickup blending.)

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