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Humbucker Dissection, Gibson Custombucker / Duncan Custom 78

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  • Humbucker Dissection, Gibson Custombucker / Duncan Custom 78

    So, I dissected a couple of humbuckers today, and was a little surprised by what I found under the hood

    I took apart a Gibson Custombucker that came in my 2012 R9, and was originally in the bridge position. Why? Because it was sitting in a box on my shelf and was never used. So, sacrifice it for learning, and what I saw surprised me. Wire appeared to be 42 PE, and guessing from the gauss measured on the magnet, it appears to be an A3 magnet, or a weakened A2...not really sure. In terms of resistance, the pickup measured 7.8 ohm. The slug coil measured 4.0 ohm and the screw coil measured 3.8 ohm. But it was in peeling back the tape and unwinding the pickup that I was rather surprised. Both coils were wound at a whopping 10 turns per layer. That's it. Equal traverse 10 turns per layer. I unwound and counted at various portions throughout the coil, and each point that I counted winds and averaged, I got 10.

    So, then I decided to dive into the custom 78 pickup that I bought many years ago and haven't used in a long time. Sacrificing for science, I wanted to see what the differences were. Wire appeared to be 42 PE, and magnet gauss was in the A2 range. I believe Duncan advertises that they use A2 magnets for the pickup. The pickup measured 9.05 ohm. Because the custom 78 is supposed to be an overwound PAF style pickup, used to get VH tones (I think bright, rich, harmonic), I expected to see something scatterwound, with maybe with offset coils. But that wasn't it at all. Slug coil measured 4.52 ohm and screw coil measured 4.53 ohm. And here's the part that was most interesting to me-- a rather high TPL count of about 96 turns per layer, equal traverse. Again, I counted in several places throughout the coil. The pickup coils were very evenly machine wound, with almost no variation and a consistent number of turns per layer.

    So, I was a little surprised. I always thought the custom 78 was a lively articulate pickup. These were attributes that I typically thought were found in pickups that were scatterwound. But clearly this pickup is a higher tpl with a very consistent wind pattern. I was also surprised that the Custombucker had such a low tpl.

    Anyhow, thought I would share. I figured it would be interesting to see what, if anything, could be learned from this simple experiment.

  • #2
    Thanks for all the info!
    Very nice data.
    My take on the TPL?
    To fatten up a low DCR pickup?
    You can lessen the TPL, which will fill up the bobbins with less DCR.
    Just the opposite for the custom 78.
    In order to get the 9k DCR on the pickup, you have to put more winds per layer.
    I wonder what the diameter of the each wire micd?
    Thanks again for sharing.
    T
    "If Hitler invaded Hell, I would make at least a favourable reference of the Devil in the House of Commons." Winston Churchill
    Terry

    Comment


    • #3
      Originally posted by big_teee View Post
      Thanks for all the info!
      Very nice data.
      My take on the TPL?
      To fatten up a low DCR pickup?
      You can lessen the TPL, which will fill up the bobbins with less DCR.
      Just the opposite for the custom 78.
      In order to get the 9k DCR on the pickup, you have to put more winds per layer.
      I wonder what the diameter of the each wire micd?
      Thanks again for sharing.
      T
      I wish I could tell. I don't really have the tools to measure the wire diameter, and other than compare it to what I have here, the best I could tell was 42 PE. That's what I thought about the the greater tpl on the custom 78--more tpl to fit more wire and get a higher resistance.

      But, I still thought there would be a coil offset, because the pickup is a rather bright pickup. I also thought that some scatter might help accentuate highs--but, who knows. Either way, it's very basic data. But, I think it gives some insight about these pickups.

      Comment


      • #4
        Is there anything more to scatterwinding than less turns per layer is there some randomness involved?

        Comment


        • #5
          Forgot to mention that the custom 78 also had a piece of shielding tape over the magnet wire coil just where the lead wire solder joint with the magnet wire would touch the coil. Not sure if this did anything significant.

          Comment


          • #6
            Now you can rewind them back if you want to.
            I have a variation of the custom 78.
            I call mine the Franken-Strat.
            I use A2 magnet, 4500 ohms on the screw, and 4700 ohms on the slug.
            Mine is probably a little rounder sounding with more on the slug.
            T
            Last edited by big_teee; 03-11-2016, 03:33 AM.
            "If Hitler invaded Hell, I would make at least a favourable reference of the Devil in the House of Commons." Winston Churchill
            Terry

            Comment


            • #7
              10 TPL seems really low and would make for a really large coil on a standard HB bobbin if it is 42 gauge wire and around 5000 turns per bobbin. Well, it is what it is!!

              Did the Custombucker coils seem very full before you started counting turns? Could be 43???...but the DC resistance seems on target for 42! Save the wire and mic it when get access to someone's micrometer.

              Thanks for the post.
              =============================================

              Keep Winding...Keep Playing!!!

              Jim

              Comment


              • #8
                Originally posted by Jim Darr View Post
                10 TPL seems really low and would make for a really large coil on a standard HB bobbin if it is 42 gauge wire and around 5000 turns per bobbin. Well, it is what it is!!

                Did the Custombucker coils seem very full before you started counting turns? Could be 43???...but the DC resistance seems on target for 42! Save the wire and mic it when get access to someone's micrometer.

                Thanks for the post.
                It surprised me too, but as I kept unwinding and counting, I kept getting 10 tpl. Coil didn't feel larger than normal. I don't think it was 43, but like I said I don't have a good way to measure. I suppose I could rewind it with the 42 I have at 10 tpl and see what I get?!

                Perhaps it's Gibson's take on a machine traversed scatter?

                Comment


                • #9
                  Originally posted by jschweid View Post
                  It surprised me too, but as I kept unwinding and counting, I kept getting 10 tpl. Coil didn't feel larger than normal. I don't think it was 43, but like I said I don't have a good way to measure. I suppose I could rewind it with the 42 I have at 10 tpl and see what I get?!

                  Perhaps it's Gibson's take on a machine traversed scatter?
                  how about you measure the resistance per foot of the wire... it may have been stretched a little in the winding process... but will give a good idea of the gauge of wire

                  Comment


                  • #10
                    Originally posted by mr fab View Post
                    how about you measure the resistance per foot of the wire... it may have been stretched a little in the winding process... but will give a good idea of the gauge of wire
                    I second that, but it can be tricky with PE.
                    I like to measure 10 feet, and I solder small 22-28awg pig tails to each end.
                    That makes measuring the wire much easier.
                    GL,
                    T
                    "If Hitler invaded Hell, I would make at least a favourable reference of the Devil in the House of Commons." Winston Churchill
                    Terry

                    Comment


                    • #11
                      Originally posted by big_teee View Post
                      I second that, but it can be tricky with PE.
                      I like to measure 10 feet, and I solder small 22-28awg pig tails to each end.
                      That makes measuring the wire much easier.
                      GL,
                      T
                      I will try this and report back

                      Comment


                      • #12
                        Originally posted by Jim Darr View Post
                        10 TPL seems really low
                        That's my experience with those too. At first I thought my process for dissecting was at fault, but when I kept getting the same results as several of my colleagues, which kept asking me the same question... well, you can draw your own conclusion on the matter, isn't it?
                        Pepe aka Lt. Kojak
                        Milano, Italy

                        Comment


                        • #13
                          So since gibson winds these R9 custom reissue pickups at 10 TPL?
                          Maybe we should discuss why, and what they sound like?
                          Do you like the sound of a 10tpl pickup?
                          Or, do we like the sound of a higher tpl pickup?
                          The 10tpl concept may be a budget decision.
                          You can fill up a bobbin quicker with less wire and less DCR.
                          You could also wind the bobbin quicker with less time and turns?
                          What's your take on the 10tpl pickup?
                          Thanks,
                          T
                          "If Hitler invaded Hell, I would make at least a favourable reference of the Devil in the House of Commons." Winston Churchill
                          Terry

                          Comment


                          • #14
                            Originally posted by big_teee View Post
                            So since gibson winds these R9 custom reissue pickups at 10 TPL?
                            Maybe we should discuss why, and what they sound like?
                            Do you like the sound of a 10tpl pickup?
                            Or, do we like the sound of a higher tpl pickup?
                            The 10tpl concept may be a budget decision.
                            You can fill up a bobbin quicker with less wire and less DCR.
                            You could also wind the bobbin quicker with less time and turns?
                            What's your take on the 10tpl pickup?
                            Thanks,
                            T
                            Is it Gibson's take on a scatter wind? I use my new CNC machine to wind pickups--by the way, if any of you are looking for an awesome machine, check out the one from CNCDesign. Sean has worked some pretty intuitive and incredible software, allowing varying tpl, saving profiles...a pitch / tpl calculator. Very cool and relatively easy to use, even for someone like me. But I digress.

                            My "scatterwind" is machine wound, and I typically keep things around 30 tpl, and I set the machine to vary the layers slightly. I try to simulate, with the machine what I might do if I hand traversed the coil. But, I've never done only 10 tpl, even when laying wire by hand. So, I'm not really sure of their reason.

                            I purchased an original set of PAFs, which now sit in the same R9. The PAFs were in a 1959 ES 335, that had a broken neck, and were subsequently put in a 55-59 burst conversion. Compared to the custom bucker, the real PAFs are brighter, more articulate, and have more "sizzle", if that makes sense. They have a slightly higher output though 8.3 (neck) and 8.5 (bridge). I have not taken them apart to measure specs...nor will I because I don't have the stones to do so. They weren't cheap. And, as long as they work and sound good, I'm leaving them alone.

                            But, there is a definite difference between the custom bucker and the original PAF in the same guitar. I've had pretty good results reproducing the sound of these PAFs in some of the pickups I've made--at least to my ear.

                            I guess I second the above question, since I really can't answer it myself. I'll defer to someone on the forum a lot smarter than me.

                            Comment


                            • #15
                              Sounds good.
                              I wouldn't mess with the PAFs either.
                              I can't really talk much of the PAF language.
                              I like neck pickups wound a lot less than that, and bridge pickups wound a lot more.
                              I think your CNC rig requires a computer.
                              I'm too lazy for that, and just wind by hand.
                              I've done it for a long while now and used to it.
                              I scatter some, but not necessarily on purpose!
                              I have the Mojo count down winder, and it is no nonsense and a fast dependable hand winder.
                              I like it OK.
                              Most of my neck pickups usually turnout like a Pearly gates, 7.2-7.4k, range.
                              Bridge pickups, I have several variations.
                              I like a FrankenStrat in the 9.2-9.4k range, I have a 42 & 43 Hybrid I like.
                              I have a A2 overwound 43 model I make most of the time.
                              Never got into the replica, or PAF routine.
                              Nothing wrong with it, I just like to make my own variation of the classics.
                              Thanks for all your Humbucker input.
                              T
                              Last edited by big_teee; 03-13-2016, 11:49 AM.
                              "If Hitler invaded Hell, I would make at least a favourable reference of the Devil in the House of Commons." Winston Churchill
                              Terry

                              Comment

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