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Theoretical Dilemma about Humbucking PUs

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  • #16
    Originally posted by David Schwab View Post
    Generally humbuckers have both coils wound in the same direction. If you wind CW and CCW then you would wire them in phase.... start-end->start-end.



    Look at it this way, you wire the two coils to have opposite polarity to cancel hum. But now they are out-of-phase with regards to the strings.

    Then you give them opposite magnetic polarities to make them in phase with regards to the strings.

    Both the magnets and the wiring puts them out of phase. Since they are out of phase twice, they are back in again.
    Yes, but you are describing a regular humbucker, isn't it?

    something like - ( -) = +

    In our particular case there's even another turn... or one less

    You wire the PUs out of phase to cancel hum,... that's the first common step...

    since the pickups sense the string from opposite sides, that's all you have to do, the out of phase wiring is already fitting (since the signal detected at each side of the strings is out of phase with each other). You don't need to have different magnetic poles on each side of the string. Doing that is alright for the regular humbucker, but not for our "one coil on each side" humbucker...

    If you wanted to use different polarities to face the strings, then you would get again an out of phase signal...

    or, you would need to sacrifice the hum canceling thing and wire them IN phase... something like slicing the coil of a single coil in two, and putting one half over the strings.

    Cheers,

    X

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    • #17
      Originally posted by xxxchange View Post
      since the pickups sense the string from opposite sides, that's all you have to do, the out of phase wiring is already fitting (since the signal detected at each side of the strings is out of phase with each other). You don't need to have different magnetic poles on each side of the string. Doing that is alright for the regular humbucker, but not for our "one coil on each side" humbucker...
      What makes you think this is true? Why is the signal from each side of the string out of phase? It's not. The string moves in a circular pattern.

      You will end up with one of several situations, the coils will be out of phase to the strings, or they will be in phase and hum. It will be the magnetic polarity that fixes it in either case.

      Wait until you build the thing and try it out, and then find you will have to swap wires around, etc.

      You have to stop thinking about it and make some tests. You can start by taking a cheap humbucker apart and move the coils around and see what you get.

      I've had pickups installed over the string many times as a test. They are not out of phase from pickups under the strings.
      It would be possible to describe everything scientifically, but it would make no sense; it would be without meaning, as if you described a Beethoven symphony as a variation of wave pressure. — Albert Einstein


      http://coneyislandguitars.com
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      • #18
        The pickup is primarily sensitive to motion along the axis of the coil. "Above" and "below" are out of phase so one reverses the electrical polarity to put them back in phase. This does cancel the hum.

        You only need to magnetize the string from one direction. If you do it from both, then one must be north and the other south. Otherwise, the fields cancel.

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