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  • Pickup output question

    A customer of mine has come to me asking me to tell him if a pickup he bought on eBay is working right. He bought a Seymour Duncan SH55 set (neck and bridge).

    Seth Lover Model™ SH-55 - Seymour Duncan Vintage Output

    He says that the bridge pickup sounds "full" while the neck pickup sounds "weak." I've checked the DC resistance of the neck pickup, and it's right on-spec.

    I'm mainly an amp tech, but I've installed pickups and wired guitars. I've diagnosed and replaced bad pickups. This is the first time someone has brought me a working pickup complaining that it doesn't "sound right."

    I'm tempted just to hand it back to him, but I'd like to help him if I can. I know Alnico magnets can get demagged if struck hard, but I'm not sure what I could do in that case. Maybe SD put a weak magnet in the pickup?

    Any ideas of how I could proceed diagnostically? Or might it be the case that it's working as designed and that he simply doesn't like it?

  • #2
    The SH-55 is a 7.2k PAF type neck pickup with a A2 Magnet.
    IMO that is about the perfect neck pickup.
    The A2 magnet is not very strong even if it is fully charged.
    If no gauss meter, you can take a piece of steel and it should stick to the poll screws, and to the slug coils, which is under the cover.
    If you have a compass then the north end of the compass needle would point to the slug coil.
    The south end of the compass would point to the screw coil.
    Usually the neck pickup sounds the loudest, because of the location, and more string movement at the neck position.
    Here's a vid that shows how to test the polarity, and other pickup tests.
    Identifying Pickup Wires & Polarities - Humbucker - YouTube
    Good Luck,
    T


    "If Wishes Were Horses, Beggars Would Ride!" Scottish Proverb 1600s
    Terry

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    • #3
      Thanks, Terry. The video pointed out one thing that hadn't popped into my head yet--that the pickup could be miswired internally. It only has two wires coming out, so maybe the internal connection between the coils was done incorrectly at the factory. I'll have to unsolder the case to open it up.

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      • #4
        Are you just checking out a single pickup, or do you have the whole guitar in front of you?
        I like to alligator clip a suspect raw pickup straight to an amp, and listen while tapping a screwdriver on it. A weak pickup will sound weak. You'll be able to hear it if it's really bad.
        If the pickup doesn't appear weak there, I would suspect the wiring in the guitar.
        Since these are eBay purchases, I would suspect post-factory errors, if there is anything internally wrong with the pickups.

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        • #5
          Before I tore it a part, I would play it in another guitar if you have one handy.
          It could also be a bad volume pot.
          With it being a factory pickup I would illuminate everything else before removing the cover.
          On import guitars the Pots can get muffled or weak sounding.
          I replace with CTS Pots.
          If you have to remove the cover here is how to do that.
          http://www.youtube.com/watch?v=uaL1ZMGNerk
          T


          "If Wishes Were Horses, Beggars Would Ride!" Scottish Proverb 1600s
          Terry

          Comment


          • #6
            I just have the one pickup, not even its mate. (The guy just dropped in with it already removed.) It could be post-factory damage or something sold on eBay because it never worked right. I don't even have a guitar in which I can mount a humbucker.

            I'm thinking that I should request that he bring in the other pickup of the neck/bridge pair for comparison.

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            • #7
              Rhodesplyr might be right here - It sounds like both wires in one coil in the pickup were switched around. This would give you a 'phased' sounding pickup (bright and trebly) with the correct ohms reading.

              ken
              www.angeltone.com

              Comment


              • #8
                Originally posted by Rhodesplyr View Post
                I just have the one pickup, not even its mate. (The guy just dropped in with it already removed.) It could be post-factory damage or something sold on eBay because it never worked right. I don't even have a guitar in which I can mount a humbucker.

                I'm thinking that I should request that he bring in the other pickup of the neck/bridge pair for comparison.
                Does it look like the cover is factory soldered, or is there soldering tracks on the back.
                It might be a rewind, or something.
                In that case I would suspect flipped coil wiring.
                I still would test it in a guitar.
                I test pickups for microphonics, by wiring them to a test jack and hooking to a amp.
                I do this with the pickup loose.
                Wave it near the amp, and see if it is hum canceling?
                If it has as much hum as a single coil, then it is probably wired wrong internally.
                T


                "If Wishes Were Horses, Beggars Would Ride!" Scottish Proverb 1600s
                Terry

                Comment


                • #9
                  Well, now that the forum is running again, I can post the resolution to this thread:

                  The leads of one of the coils were flipped such that they were wired - + / + - according to the pull-off test. Wiring them - + / - + made the customer happy.

                  Thanks for the help!

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