Installing a coil tap switch

Discussion in 'Just Pickups' started by Craig Williams, Aug 20, 2021.

  1. Craig Williams

    Craig Williams Tele-Meister

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    Installing a coil tap switch on my guitar. Just going to use a SPDT micro toggle. I dug up the diagram below but trying to get my head around it. Currently South and North finish wires joined together.

    I assume the middle lug is common and the switch selects 1 or 2. I can see where in position 1 it leaves the North / South finish wires still joined but isolated so will get the full HB effect.

    But I can't get my head around the number 2 position? It looks like the circuit will have a path through the South coil to the output, but also a path through both coils as well through the North Start cable to out put?

    What's happening here? Does it simply take the path least resistance from South finish straight to output rather than going through the North coil?

    Does the circuit look correct?

    InkedScreenshot 2021-08-20 072845_LI switch.jpg
     
  2. Craig Williams

    Craig Williams Tele-Meister

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    Well I don't really now, but thanks for your reply. The first pic link makes even less sense to me? If the middle pin is common, you would only get output to the volume control in one position? I am sure I must be reading this wrong
     
  3. cpage86

    cpage86 TDPRI Member

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    Assuming you just want a traditional coil split (north coil active) -

    Easiest thing to do is to just switch the joined wires (N and S finish) to ground to short the bottom coil. This leave just the north coil active.

    1. Install you pickup as usual in the series fashion (hot to controls, ground to ground)

    2. Instead of taping/heat shrinking off the two coil wires like usually done, take those two wires to the middle lug of the SPDT switch

    3. Solder a wire from either the top or bottom lug (doesn't matter which one) on the SPDT switch and to your ground

    That's it. In this fashion you'll get series humbucker in one position and coil split in the second (by running coil 2 to ground)

    EDIT - your diagram, after looking again is essentially doing the same thing I have described above, but your diagram is switching to just the south coil, not the north coil. Instead of switching the south to ground like I describe, they are shorting the north coil to HOT. This provides just a path for the south coil to be connected. So in pos 1 the switch is down, allows regular series humbucker. Pos 2, the switch is up shorts the north coil, and leaves the south coil in.
     
    Last edited: Aug 21, 2021
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  4. warrent

    warrent Friend of Leo's

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    The North coil is shorted out of the circuit both the start and finish are combined. It's one way to do it, usually I do this:
    coil_tap.gif
     
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  5. Craig Williams

    Craig Williams Tele-Meister

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    Oh Ok I can see how that would work. When you close the switch you short the South coil to ground? And ground goes directly to North Coil and other side of the North coil out to controls?
     
  6. cpage86

    cpage86 TDPRI Member

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    I was just trying to add this same picture! Thanks! This is a great diagram.

    Uses a DPDT switch, but that is just two independent SPDT ganged together. Just focus on the one that is used.
     
  7. Craig Williams

    Craig Williams Tele-Meister

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    My HB has a coil with screws and one with normal poles. The adjustable pole coil is South. Which one would be best to use?

    Is there any better method as far as not introducing hum or electrical noise?
     
  8. cpage86

    cpage86 TDPRI Member

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    depends

    what location is it? what sound you looking for? you had a coil split guitar before? know what you like?

    function will be identical no matter where it goes, going to single may introduce noise

    If you want to stay noise free, consider going the Series/Parallel switching path (requires DPDT switch). Parallel gives almost a single coil sound, but still remains noise free like a humbucker does.
     
  9. Craig Williams

    Craig Williams Tele-Meister

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    Not sure on my color combination it is a standard HB pick up off an 80s Yamaha. There are two wired twisted together at the moment. Other two wires going to ground and controls.

    The two wires twisted together I assume are the Finish of one coil and the start of the other coil?
     
  10. Craig Williams

    Craig Williams Tele-Meister

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    I can live with single coil noise, no I mean like back feed, ground buzz or other introduced electronic noise
     
  11. cpage86

    cpage86 TDPRI Member

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    You're assumption is most likely right.

    I'd follow the diagram @warrent posted with your SPDT switch.
     
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  12. warrent

    warrent Friend of Leo's

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    Is this for the bridge or neck position? Usually you use the outside coils for the split, so coil closest to the bridge or coil closest to the neck.

    It's the finish of the south coil and the north.
     
  13. Craig Williams

    Craig Williams Tele-Meister

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    Its the bridge coil, the coil closest to the bridge has screws / adj pole pieces if that makes a difference. Why are the two finish wires joined? Out of phase for hum cancelling?
     
  14. Peegoo

    Peegoo Doctor of Teleocity

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    It blows my mind that there are guitar Websites that contain instructions on How To Do Stuff, and they call a coil split a coil tap. They are different things.

    A tap is a connection within a single coil that electrically shortens the length of the coil:

    [​IMG]
     
  15. moosie

    moosie Doctor of Teleocity Silver Supporter

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    With Duncan colors, typically, and the way it's drawn, green is common, connected to ground. Imagine electrons boiling up from there, through that south coil, coming out the 'hot' end, and then directly into the backside (as it were) of the north coil. That's a series circuit, like two boxcars hooked up end to end. Then the electrons keep going, out the hot side of the north coil, to the switch, etc.

    If you connect a wire to that middle junction, and attach it to 'hot' (switch, vol pot input, etc), then the north coil is shorted out (silent). It's a shorted loop, hot connected to hot. And simultaneously, the south coil's hot is STILL connected to hot, but this time without the north coil in the way. It's green (start) is still grounded, so we have a normally wired coil.

    If you move your added wire, to connect it to ground instead of hot, you short (and silence) the south coil.

    Get it?
     
  16. gkterry

    gkterry Tele-Afflicted Silver Supporter

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    The difference is the diagram below (which is the one from the first link in post #2) is using a 3-way SPDT switch: on-off-on. Essentially with it in the middle (off) position it is using both coils - normal humbucker.

    Either of the other two switch positions, only one coil is active. Seems like the coil that is normally used in a coil tap is the one with the screw lug pole pieces and the other is not normally used.

    upload_2021-8-21_3-5-30.png
     
  17. moosie

    moosie Doctor of Teleocity Silver Supporter

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    There's nothing making that necessary. You can deactivate either coil, as you've pointed out with that on-off-on switch. One consideration could be hum cancelling, say if you have an SH guitar, or HH where both humbuckers are split. Another could be that you want to hear the coil which is in a particular position under the strings: closer to the bridge, split pair farther apart, etc.
     
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  18. Craig Williams

    Craig Williams Tele-Meister

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    Put the micro switch in this morning. Simply got the wires that were twisted together and soldered them to the common (middle) lug, and ran the other lug of the switch to ground. Last lug not connected. Seems to work well. It is switching the North coil (pole pieces / not screws) though. Thanks for all the advice guys
     
  19. moosie

    moosie Doctor of Teleocity Silver Supporter

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    If you want the other coil to be active instead, simply move your grounded wire, to hot. Vol pot input, or the blade switch lug leading to that. Then you'll be using the screw coil.
     
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