need a little switch wiring help

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by m-m-m, Feb 16, 2012.

  1. m-m-m

    m-m-m Member

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    I haven't spent too much time wiring mini toggles and I want to make sure I've got it right before I start the job. I've got a guitar that I'm adding a pickup to. The neck humbucker is wired to a on/on/on mini switch that gives it series/split/parallel that I never use. I'm adding a middle pickup and I want to re wire the mini switch to give me Neck/n+m/middle.
    Using this diagram I should wire the hot pickup leads to the following lugs:
    [​IMG]
    a1 - empty
    a0 - jumper to b0
    a2 - neck pickup
    b1 - middle pickup
    b0 - jumper to a0 and output (to another 3 way toggle actually)
    b2 - empty

    makes sense to me, anyways. If I'm right what I'll end up with the mini switch a selector for middle and bridge pickups and then the normal 3 way toggle will select between bridge and whatever is selected on the mini.
     
  2. John Coloccia

    John Coloccia Cold Supporting Member

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    Sounds good to me. Personally, though, I think a 5 way super switch would be more convenient. You can easily do, B/B+M/B+N/M+N/N. This is how I configured my Wolfgang, actually, after adding a middle pickup.
     
  3. m-m-m

    m-m-m Member

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    I get where your coming from, but this is actually more convenient for the way I tend to play and swicth pickups.

    but I was thinking ...

    a better option for me may be a 6 way rotary switch wired like this:
    keep in mind that these are all 5-wire hb's
    1- Neck
    2- neck and mid wired in parallel
    3- neck north + mid south wired in parallel
    4- mid
    5- off
    6- neck attenuated - I've been thinking lately that I like the idea of wiring a resistor to a switch to give you quieter more bassy sound from a given pickup, but I know noting about resistors. Something roughly equivalent to halfway 500k pot would be great. hmmm. Does that mean I need a 250K resistor?

    wire that to the 3-way toggle like I mentioned in the OP. I should be able to figure out a lot of the wiring, but it'll take me some time, so any assistance would be greatly appreciated.
     
  4. m-m-m

    m-m-m Member

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    bump! --- anybody got any input on my last post??
     
  5. Clorenzo

    Clorenzo Member

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    To simulate the vol. control halfway, you need a resistor in series and another one to ground. A typical 500k log (audio taper) pot on 5 has about 450k between input and output and about 50k between output and ground (it would be 250k / 250k if it was linear taper), so you could use 470k (standard value) in series and 56k (also std.) to ground, which, in parallel with the 500k of the "real" volume pot, will give you the required 50k. You may want to use trim pots rather than fixed resistors to be able to fine-tune the amount of attenuation to your taste.

    If you use one of these (the 6-pos. / 2-pole one):

    http://www.stewmac.com/shop/Electronics,_pickups/Components:_Switches_and_knobs/Rotary_Switches.html

    and assuming Seymour Duncan colour codes (if different brand just find the equivalences), wire as follows:

    Neck White + Bare to ground
    Middle Green + Bare to ground

    Switch pole A:

    Neck Red to 1 and 2
    Neck Black + Green to 3
    5 to ground
    56k resistor between 6 and ground

    Switch pole B:

    Middle Black to 2 and 4
    Middle Red + White to 3
    5 to ground
    470k resistor between 4 and 6

    Both switch "0" lugs jumpered together and to the main toggle switch

    Note that in the off position the output is grounded, so it will also be off when the main toggle is in the middle position. Note also that in the neck attenuated position there is a 56k resistor to ground that will load the bridge pickup when the main toggle is in the middle position, so the sound will be quite dark, as if the tone control was turned down, and there will be very little contribution from the neck pickup due to the series resistor. Basically your toggle will do neck attenuated / bridge rolled-off / bridge.
     
  6. m-m-m

    m-m-m Member

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    Thanks so much for your input. That's so much more info than I expected. The trim pot is interesting, and i see the potential benefit. I'll have to look for one of those, as I've never see one at my typical parts sources.

    Thanx again.
     
  7. Clorenzo

    Clorenzo Member

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    Trim-pots are available from www.digikey.com , www.mouser.com and www.newark.com . The problem is that they cost just a few cents and these guys have minimum orders and then there's shipping. To make things simpler, you could stick with the fixed series resistor and use this from Radio Shack for your ground resistor. Then if you find that even on is highest setting you get too much attenuation, try a few smaller values for the series one, for example 330k, 220k, 150k and 100k (resistors are also cheap so it's a good idea to get a bunch of them and experiment).
     

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