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electronics/wiring mods, etc.

Discussion in 'Luthier's Corner' started by complexprocess, Jan 13, 2003.

  1. I'm looking for info on wiring mods and the like. Anybody have any good resources (especially bass-specific ones)? I also have a question or two. First, some backing story:

    I've got an old, glam rock era (by the looks of it) washburn that I picked up at a yard sale for $15. It was fun to play around with, and now I want to explore restoration/building with it. My plan is to replace the neck with a carvin bolt on (by the specs it should be a perfect match to the original) and then replace everything, from pickguard to wiring to paint with new and or custom parts. I think that when it's all said and done I will have a decent passive rocker that really looks the part. Currently there is a single p-style pickup, tone, and volume. My plan is probably to replace it with a single humbucker, similar to the music man. maybe just for kicks while I'm fabricating pick guards I'll consider some strange configuration like 3 jazz pickups but I'm looking to avoid routing so maybe not.

    Anyway, on with the questions. I'd like to do some sort of unique wiring to make this my own. I know different capacitor values alter tone. Any guesses as to what two capacitors in series might do? What about different valued ones in parallel? Any other wiring tricks that people know of to get great tone (I understand that it's highly subjective). I'm hoping to stay with an all passive setup, FYI. As far as tone is concerned I'm thinking a "growly" hard rock typed tone that can supply a good amount of tight punch if called upon.

    I understand that I've asked for a bunch of piecemeal info, but I'm sure this thread will help future builders as well as myself. Thanks for any insight or resources you guys (people?) have.

  2. Trevorus


    Oct 18, 2002
    Urbana, IL
    Well, to answer your questions about the capcitors, they are the opposite of resisitors in the mathematical combination effect. Capacitors in series are determined by it's capacitance value(usually in microfarads), or n.

    1/n1 + 1/n2 = 1/n(combined) you do the algebra. But in parallel, you can do it the easy way. again, n:

    n1 + n2 = n(combined)

    so, there you have it.

    www.guitarwiring.com has some good resources. Just do a web search at google, you can find anything through that.
  3. Looking at the p-bass wiring diagram linked below, I've come up with an idea that seems a bit silly, but might be fun. I'll stick to P wiring for now and worry about a humbucker later. Let me know if any of this sounds logical to you.

    From what I've read, higher capacitance causes greater trebel cut (more bass). Could it be possible, then, to remove the tone pot entirely in favor of a bank of switched capacitors and a fixed resistor (say 250Kohm)? For example, where the tone pot is, could I wire in parallel x number of capacitors with a separate switch to include/exclude each one? In effect for each switch that was on I would be addind the capacitance value of that "section" to the total. I believe I could also add a full bass switch that simply bypasses the resistor/tone section all together (I think). I'm not as up to speed on my electronics as I would like, does any of this seem valid to anybody?:confused: Thanks a bundle for putting up with my crazy questions.

    Oh, and here's the link I was looking at. Thanks again.
    P-bass Diagram
  4. FBB Custom

    FBB Custom TalkBass Pro Commercial User

    Jan 26, 2002
    Owner: FBB Bass Works
    The function of a tone pot is to bleed a certain amount of the signal down the capacitor's path to ground. You could use the bank of switches without the resistor, but you would would be only able to vary the treble cut threshold, and not the amount of treble you roll off.

    I think your best bet is to insert the bank of switches where the capacitor is in your P bass wiring diagram and leave the pot in there.
  5. What if I used a fixed resistor to bleed a sertain amount down, and then switched that amount with the capacitor array? or switch between a couple of resistors, each of which leads to the capacitors? I just really think it would be cool (not so much practical) to have a bass without knobs.

    Alternately I could try using a slide pot, but I haven't seen any of the "audio taper" variety.
  6. pilotjones

    pilotjones Supporting Member

    Nov 8, 2001
    If you just like the look of switches instead of knobs, how about this: leave one standard value capacitor; replace the tone pot with a bank of resistors, wired in parallel but interrupted by switches. No switches on = no treble shunt to ground; add more resistors (starting with a high value one) to gradually short out the treble (just like the pot does normally).
  7. That could work well. Thank you. I hope to start working/ testing soon.
  8. Razor


    Sep 22, 2002
    notduane is a really knowledgable person when it comes to bass electronics. Might send him a message...FWIW
  9. jbay


    May 23, 2002
    Sorry to the original poster, dun mean to hog the thread but does anyone know if I could do a passive mid bleed without using an inductor? I'm trying to use a push/pull pot to select between cutting 2 diff freq, specifically 2kHz and 630Hz. What capacitor values should I be looking at? Thanks...
  10. pilotjones

    pilotjones Supporting Member

    Nov 8, 2001
    I think that any kind of band pass/cut, as opposed to hi/lo pass/cut, requires an LRC circuit, and therefore an inductor. Anybody confirm this?
  11. thrash_jazz


    Jan 11, 2002
    Ottawa, Ontario, Canada
    Artist: JAF Basses, Circle K Strings
    IIRC that is correct.

    An interesting mod I recall reading about was to replace the tone pot with a switch, which was wired to capacitors of different value.

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