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The Ultimate Passive J-bass Wiring Scheme

Discussion in 'Pickups & Electronics [BG]' started by azwipe, Feb 7, 2014.

  1. azwipe

    azwipe Supporting Member

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    From right to left:

    1. 500k volume control, with the S-1 switch for series/parallel on both pickups individually. (Pickups are DiMarzio Model J)
    2. 250k blend control, ungrounded and works great.
    3. 3pdt switch for both pickups series/parallel together, and bypasses the blend control.
    4. multi-purpose, 500k tone pot with "no-load" mod.
    5. dpdt, on/on/on switch. This moves the tone pot between a .022 cap, a .1 cap, and... a Bill Lawrence Q-filter.

    Notes:
    The order of the wiring "under the hood" is different from the logical, user-side order of the knobs and switches.

    The switch for individual pickup series/parallel is probably the least useful. Parallel mode doesn't seem to change the tone, just reduce the output. Which is occasionally helpful for a quick volume drop.

    Individual pickups in parallel while both pickups are in series sounds to my ears identical to individual in series, both in parallel (assuming the blend is centered)

    Everything in series sounds great! Huge, ballsy lower mid and output boost for when you feel like being a bully. Muddy for some things maybe, but cuts through a mix just fine.

    The Q-filter is actually really cool, especially for slapping. It cuts volume and lower mids while preserving (even accentuating) highs. So slapping doesn't mean you get twice as loud. Granted, that problem can also be fixed with technique, but this opens up other stylistic possibilities.

    Full disclosure: It all works fantastic and fits in the standard control cavity, but it's a serious rat's nest in there. A better man than I could probably make it pretty.

    Attached Files:

  2. dls119

    dls119

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    Diagram please! Or at least a rats nest shot.

    Very cool setup.
  3. azwipe

    azwipe Supporting Member

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    Oh, man. Honestly I don't have one and don't know how to draw this in a way that's legible. This was the bastard child of several diagrams that I found on Talkbass and elsewhere. I'll see if I can find those and link to them.

    Az
  4. dls119

    dls119

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    No problem - I just got into wiring and customizing with electronics so I was curious to see what you did.
  5. line6man

    line6man

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    You can do series/parallel with a blend, using only two poles, if you don't mind an ungrounded blend.
  6. Koeda

    Koeda Supporting Member

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  7. CoarseBass

    CoarseBass

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    How are you switching each pickup individually with a single S1 switch?
  8. line6man

    line6man

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    The Fender S-1 is 4PDT.
  9. azwipe

    azwipe Supporting Member

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    That's right. I couldn't find a way to fit a regular 4PDT miniswitch in the cavity without routing.

    I guess I should clarify that the S-1 switches the individual pickups simultaneously from series to parallel. I did experiment with independent switching for the two pickups but found the tonal differences were not noticeable enough to be useful.

    Az
  10. michaelandrew

    michaelandrew The bass player is always right. Supporting Member

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    Nice.

    I tried a 500k "no-load" tone pot on my J - found I couldn't tell the difference between 500K and "open" in the tone circuit. What's your experience?
  11. azwipe

    azwipe Supporting Member

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    You know, I can't really tell the difference either. But it's nice to know that when volume and tone are maxed out and the blend is centered, the only things between the pickup coils and the amp are the volume pot and instrument cable.

    The only thing I'm thinking of changing is the tone pot - I want to experiment with a 250k "no-load" pot and see if it gives a smoother taper. That was certainly the case with the blend pot, which behaved like a selector switch when I had a 500k blend in there.

    Az
  12. azwipe

    azwipe Supporting Member

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    That's pretty rad, Koeda. Like a Strat bass. Where'd you get that pickguard?

    Az
  13. michaelandrew

    michaelandrew The bass player is always right. Supporting Member

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    FWIW - I use 500K pots for bass and treble (stacked) - with 500K volume and blend. The "bass" control is really a treble cut with a 0.01 uF cap - with the bass control at zero, the cap is bypassed.

    The "treble" control is just the usual J-bass pot+cap-to-ground arrangement but using a 0.1 uF cap (rather than 0.047). I also use a separate series/parallel switch.

    Regardless of the lay-out, I've found I get the smoothest control using all 500K pots, but audio taper, for tone; linear taper, for volume; and NM taper for blend. I also like a "treble bleed" on the vol pot - 100K||uF. YMMV (and my opinion may change at any moment:)).

    Pic's of the different control plates I've tried are somewhere in the "Tricked out Squire" thread - I'll post a link when I figure out how.:meh:
  14. michaelandrew

    michaelandrew The bass player is always right. Supporting Member

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  15. Koeda

    Koeda Supporting Member

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    Tanx - that one is a do it yourself model.

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