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DIY wiring - help needed

Discussion in 'Pickups & Electronics [BG]' started by stradivarius151, Mar 14, 2016.

  1. stradivarius151


    Jan 18, 2014
    Hey everybody,

    I am DIYing something different, and very unusual, simply because I wanted to try it and there is nothing like it in any store that I have run across. It involves a very guitar-like control system unlike what most basses use.

    I have three passive pickups (N/M/B). I have a three-way Les Paul style switch that goes N, N+B, B (like a typical two-pickup guitar). That then went into a volume and tone for those two pickups. Then for the M, I decided to have a separate volume pot (in parallel with the other circuit, of course). I thought this would allow me to make a selection of N/B, and then fade in M as I pleased.

    There was a problem. Turning the M volume down to 0 didn't get rid of all of the sound from M - there still was a little bit left in the signal, verified by tapping on the magnets with a metal screwdriver. Apparently Les Pauls suffer from this problem when in the middle position, because of the nature of passive components - turning down the volume for one doesn't completely remove it from the signal.

    I decided to put in a switch - I wouldn't ever need to try fading M in, and it would completely remove the pickup from the signal. Even though I was using two separate switches, I still was just making and breaking connections, right? Wrong - turning that switch off does exactly the same thing as the pot did on 0.

    So what am I missing? How can I set it up so that the middle pickup is completely off when I turn it off? I really hate getting the sound of multiple pickups, even slightly, when I am aiming for the pure sound of either N or B. Thanks!
  2. stradivarius151


    Jan 18, 2014
    Just FYI - this was partly inspired by a bass owned by Tiran Porter, formerly of the Doobie Brothers. He showed it off in an interview which I now find has been removed from YouTube for copyright. But it had a Gibson EB pickup in the neck, a P pickup in the middle (it's normal position), and then a J pickup in the bridge. Looked awesome and it sounded great. I can't even find a pic on Google Images.
  3. Hopkins

    Hopkins Supporting Member Commercial User

    Nov 17, 2010
    Houston Tx
    Owner/Builder @Hopkins Guitars
    Something isn't making sense. If you shunt the pickup to ground like your volume pot should do, there is no way it should still be in the signal. If you open the circuit with a switch, it should also be removed from circuit.
  4. 40Hz

    40Hz Supporting Member

    +1 w/Hopkins above. Something isn't making sense here.

    Any chance of posting a wiring diagram or schematic so we can see what's actually been done? That would be more helpful than a description, which may or may not reflect the circuit accurately.
  5. stradivarius151


    Jan 18, 2014
    Yes, sorry, this got away from me. Pardon the non-electrical engineer formatting, and ignore the blue scribbles in the upper-right hand corner. That was a mistake.
    Blue is ground wires, however, I don't have them all on there because I don't know where they all are. Could it be possible that the signal from the middle pickup is leaking through the grounds somehow and making its way to the output jack somewhere? If the pickup has a hot wire and a ground wire, and the hot is completely disconnected, that would have to be the case, no?

  6. Your tone control is not wired to do anything. Also, there is no capacitor.
    WRM likes this.
  7. stradivarius151


    Jan 18, 2014
    Like I said, this is missing lots of wires. What would I be missing above, because it definitely works in real life?
  8. Without a capacitor, a tone control is simply a volume pot.

    As shown in the diagram, the tone control is not even in the circuit. Every connection to the pot is to ground.
  9. stradivarius151


    Jan 18, 2014
    Oh, yeah, I thought you meant in terms of wires. Would there actually be something on that first lug? I somewhat copied the design from an HSH strat a friend put together, with a similar concept. His humbuckers were pre-wired from a PRS guitar, which gave him a volume and tone pot. He basically took that and then added the middle pickup/switch. I basically did the same thing with this, so I pretty much copied straight from the official document for that guitar on PRS's website, which shows the tone pot exactly as I left it up there.
  10. Will_White


    Jul 1, 2011
    Salem, OR
    Ok here's what I would do, take the diagram from a jazz bass make the middle pickup be the bridge pickup, and the output from the switch be the neck pickup, wire the switch as you would normally, and take the hot and the ground off the switch to be the hot and the ground of the neck pickup in the jazz bass diagram, that gives you the options from the switch and you can blend the middle pickup in to those, or you can get the middle pickup by itself. In guitar parlance I think this would be the equivalent of a Nashville strat. If you need a diagram I can make you one, if @line6man doesn't beat me too it.
    The wiring diagram you posted is missing too much to really be useful.
  11. SteveCS


    Nov 19, 2014
    Hampshire, UK
    Try this for size, per your original requirement...

    3-Pup with Mid Blend.JPG

    I've not shown pot or cap values, but personally I would use 500k linear for the volumes and 250k log/audio for the tone pot. Cap value is up to you. Note that 1) by backing off the N/B volume you can isolate the tone pot from the middle pup, and 2) there will no tone control for the soloed mid pickup.
    Will_White likes this.
  12. stradivarius151


    Jan 18, 2014
    I understand everything your post says, but I definitely don't have a ground wire coming out of or on the back of either switch.
  13. stradivarius151


    Jan 18, 2014
    Can someone please answer this?
  14. Will_White


    Jul 1, 2011
    Salem, OR
    Your switch should have a ground lug.
  15. stradivarius151


    Jan 18, 2014
    Would this be causing the leakage of the middle pickup?
  16. Will_White


    Jul 1, 2011
    Salem, OR
    No, it just makes the switch noisier, and makes wiring more complicated. Also signal doesn't go through grounds, so the middle pickup wouldn't be leaking through the grounds.
    Are you using a mini switch or a Gibson switch for the selector?
    Last edited: Mar 29, 2016
  17. stradivarius151


    Jan 18, 2014
    It's a strat switch which was lying around, also it allows me to shut both neck and bridge off. N/N+B/B/B/nothing
  18. Will_White


    Jul 1, 2011
    Salem, OR
    If you've got a strat switch why don't you wire it like a seven sound strat?
  19. stradivarius151


    Jan 18, 2014
    I like this setup better, and want to figure out how to make it work.
  20. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009

    the problem is the "independent" pot, with the pickup going to the middle lug; you get a slight residual signal with it "off".

    gibsons don't have this problem because they don't do independent volumes; turn one volume all the way off with both pickups on and it kills the entire signal. it's a tradeoff they don't make because besides "off" being truly off the sweep and tone is better when you turn down.
    stradivarius151 likes this.

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