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series/parallel wiring: help please!

Discussion in 'Pickups & Electronics [BG]' started by Mabrothrax, Jul 25, 2012.

  1. Mabrothrax


    Dec 21, 2007
    East Sussex
    Hi all,

    am in the swing of a frankenbass MM/P build and am having issues with wiring a switch.

    I'm using a DPDT on/on/on switch. I have used the readily available wiring diagrams (seymour duncan etc).

    Only when switched to parallel does anything work, the other two positions doing sod all.

    I can't find any real variation on schematics other than swapping the green and white around (which I've tried).

    As far as I know for parallel wiring red & black combine to make the +ve connection and white & green the -ve.

    Got that working. Series is black for +ve and red & white for -ve, yes? None of the switching diagrams seem to allow that to happen?!

    Please can someone give me a clue.

  2. FunkMetalBass


    Aug 5, 2005
    Phoenix, Arizona 85029
    Endorsing Artist: J.C. Basses
    Are you wiring the MM coils in series/parallel, or are you trying to wire both pickups in series/parallel with each other? What pickups are you using? If you're unsure which coils belong together, grab a multimeter and check for continuity.

    EDIT: Also, why do you have an on-on-on switch for series/parallel?

    For a standard on-on DPDT switch, this diagram (where the blue is your white wire) should work ya. Again, you may have to swap the blue and green.


    Depending on your on-on-on switch type, I think this diagram will make the middle position single coil (neck coil) mode.
  3. Mabrothrax


    Dec 21, 2007
    East Sussex
    Sorry, didn't explain too well.

    It's the MM pickup that I want to wire series/single coil (south)/parallel

    I'll try your diagram, but something looks odd - aren't the black and red the +ve/hot wires? If so how come you've the green (-ve) going to the output?

    I'll give it a try anyway, thanks.


    using your diagram I get sound in all positions, but I'm not sure there's any sonic difference between the positions...
  4. FunkMetalBass


    Aug 5, 2005
    Phoenix, Arizona 85029
    Endorsing Artist: J.C. Basses
    The symbols +/- are mainly used to distinguish direction wires as they pertain to coil phasing. In a passive pickup, it doesn't matter which wire you consider to be the lead, just as long as you get the second coil to be in phase with the first.

    Try setting your amp flat. You should notice a bit of a difference in the two outer positions. The middle position may be harder to distinguish.
  5. Mabrothrax


    Dec 21, 2007
    East Sussex
    Well the beast is born, but there's some strange behaviours going on...

    It's passive V/T, with an MM style pickup wired to a 3 way on/on/on as the above diagram - that in turn is connected to another 3 way wired to the P pickup and the out put to the volume.

    Thing is... the series/coil/parallel switch seems only to work when the pickup selector is in the middle position (MM+P)?!

    On their own the P and MM have robust and distinct sounds, although the series/coil/parallel switch does nothing to the soloed MM pickup

    Bizarre :eyebrow:

    the selector DPDT is wired:


    P = p pickup, X= output, M = MM pickup, each pair is connected.

    Any ideas?

    Thanks :meh:
  6. FunkMetalBass


    Aug 5, 2005
    Phoenix, Arizona 85029
    Endorsing Artist: J.C. Basses
    Care to draw out a diagram of how you have it wired? It'll be much easier to pinpoint the issue.

    Also, for your on-on-on switches, is yours a type 1 or type 2 (see below)

  7. Mabrothrax


    Dec 21, 2007
    East Sussex
    see attached diagram.

    Don't know which type of DPDT, is it noted on the switch itself somehow?

    Incidentally, tapping the pole pieces of each pickup in each configuration suggests it should work.

    Selector on P position the P sounds full,

    in MM+P position the sound of the MM is effected by the series/single/parallel switch but sounds reduced in volume overall and tapping the P pup pole pieces makes a click, although it appears to have no presence.

    In MM position the pup sounds full and robust but the series/single/parallel switch has no effect except that the poles click when tapped both rows or single depending on the switch position.

    Attached Files:

  8. brainburst


    Jan 10, 2012
    bronx ny
    Yeah your wiring is totally wrong. in one position it is just shorting the coil. Usually the center poles are the ones that are being switched. You should first draw a schematic of what you are trying to achieve with switches before a wiring diagram. Their not the same thing.
    I don't believe it is possible to do series single parallel with one double pole switch. There are too many points that are being switched. If you draw as a schematic with the coils drawn in the circuit (not just leads from the pickups) it will become clear.
  9. Stealth


    Feb 5, 2008
    Zagreb, Croatia
    You can do Ser/Sin/Par with a DPDT.


    Courtesy of Line6man.
  10. yooloo


    Nov 30, 2005
    Paris, France
  11. Mabrothrax


    Dec 21, 2007
    East Sussex
    Thanks, I have and have been using the bartolini schematics. Pretty sure it's a type 2 switch that's the issue.

    Rather annoyingly I've seen conflicting info on how the middle position of a type 2 DPDT on/on/on actually connects, even in this thread.
  12. FunkMetalBass


    Aug 5, 2005
    Phoenix, Arizona 85029
    Endorsing Artist: J.C. Basses
    There may even be three types. I'll have to go dig around some mfg specs.

    If you're not sure which you have, check continuity between the center and outer terminals in each switch.

    EDIT: I just went through and checked the specs of every mfg of which Mouser sells an on-on-on DPDT switch. Of the 6 I found, C&K, NKK, and Honewell all listed the positions according to Type 1; Apem didn't list the terminal connections for the middle position, which tells me it's probably like Line6Man's Type 2; and TE and E-switch didn't seem to have terminal connections listed in their specs.

    So, if I had to guess based on this sampling, I'd say that the diagram I originally found online and posted is wrong and Line6Man's is correct, and that would explain why you're having trouble with your MM/P switch. I still recommend checking terminal connections on your switch, but that does seem like the most likely culprit at this point.
  13. Mabrothrax


    Dec 21, 2007
    East Sussex
    Not only was it a type 2 switch (or so it seems) but it was also a duff one.

    Having now got a type one and wired the MM pickup to it it sounds beastly and works perfectly. Many thanks to all who chimed in.

    Now to wrestle with the preamp I have. If I can figure that out and drop it in... oh my.

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