Jazz bass pickups with treble bleed problem

Discussion in 'Pickups & Electronics [BG]' started by Spirit of Ox, Jun 21, 2019.

  1. I ordered this harness and when I installed it, I soldered the pickups to the center lug on each volume pot and ground to back of pot. I'm using Fender Pure 74 Jazz pickups.
    I'm experienced at installing pickups but for some reason when I turn down the pickups volume pots it cuts all the treble. It's like it's working as a tone/vol in one.
    Aren't the treble bleed caps supposed to keep your tone from losing highs when turning down volume?

    Custom Shop Jazz bass Wiring Harness! High Quality, Great Sound! | eBay
  2. PawleeP


    Oct 8, 2012
    East Coast
  3. Clark Dark

    Clark Dark

    Mar 3, 2005
    That's how the treble bleed cap is supposed to affect the volume pots. Are the volume pots B250K ? That would be a linear taper volume pot.

    EDIT: I looked at all the pics on the sale page and see the pots are audio taper. Audio taper pots have a narrower range than linear taper pots. For example from 0 to 7 you might not notice a difference in volume then from 7 to 10 the pot is all in. With a linear taper pot you see an increase in volume gradually from 0 through 10.
    Last edited: Jun 21, 2019
    Spirit of Ox likes this.
  4. They just say 250k. I was told These pots aren’t supposed to cut treble with those caps on them.
  5. I guess you could check that the caps are 1nF ("102"), but TBH I'm not sure treble bleed caps would do much on a VVT. Notice the pickups wired to the centre lugs, unlike single vol guitars where the hot is wired to the clockwise lug. The treble loss with VVT is more to do with the resistance between the middle lug and earth, not the resistance between the middle lug and hot, where the bleed cap is.

    I'm not sure I've seen a passive circuit, bleed caps or otherwise, with two volumes that didn't have this tonal effect. You are right, the volumes are essentially tone pots as well because they load the pickups more and more as they are turned down. That's exactly how a tone pot works (for most of its sweep, anyway).

    You might have more luck with an unearthed blend pot instead of two volume pots.
    PawleeP likes this.
  6. thisSNsucks

    thisSNsucks I build Grosbeak Guitars and Basses Supporting Member Commercial User

    Dec 19, 2004
    Yonkers, NY
    Grosbeak Guitars
    Make sure that the legs of the treble bleed cap/resistor aren’t bent in a way that they’re grounding out to the pot or anything else.

    They shouldn’t be touching anything except the lugs on the pot.
    Spirit of Ox likes this.