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Wiring SH-1 vs. P-Rails

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  • Wiring SH-1 vs. P-Rails

    I have a set of P-Rails in one guitar wired with two push-pulls to allow humbucking, just the P part or just the rail part. I love it! As I understand it, the P-Rails are wound to allow the inner coils to be hum-cancelling when you do this (and in phase and all of that) and the outer coils to be hum-cancelling as well.

    I also have a set of '59s in another guitar (Tele Deluxe style with two volume and two tones, plus a three-way switch). I'm wondering if I can apply either of the two P-Rail wiring diagrams to other Duncan humbuckers and get the same results.

    In other words, using the Duncan diagram for P-Rails, will it allow me to select the inner coils and/or the outer coils of the '59s if I follow the scheme completely.

    If so, will the '59 inner coils be hum-cancelling with each other in the same way that the inner coils of the P-Rails are? Same for the outer coils?

  • #2
    Re: Wiring SH-1 vs. P-Rails

    Oops, made a mistake. I have a set of '59s in a different guitar.

    The one I'm actually asking about has the Hot Rod Set: JB and Jazz. I'm guessing the answer would be the same whether I was talking about any normal SD humbucker.

    Comment


    • #3
      Re: Wiring SH-1 vs. P-Rails

      Thanks. I did a little more searching and learned quite a bit. Per customer service at SD on the phone today:

      Most "normal" Duncan humbuckers have the adjustable coil as South (outside coils for neck and middle). The South coil always has the green and red wires. The North coils are the slug coils on the inside, with black and white wires. Thus, from fingerboard to the bridge, the individual coils run South-North-North-South.

      P-Rails are very different. The P-90 coil in each pickup are on the outside, and whether neck or bridge, always gets the green and red wires. In the neck, the P-90 coil is North. In the bridge, it's South. The inner rail coils always get the black and white wires. The rail is South in the neck and North in the bridge. Thus, from fingerboard to the bridge, the individual coils run North-South-North-South.


      I guess it would reqiore some figuring to up with how to modify the P-Rails diagram to two different coil combos. To maintain hum-cancelling, the inner vs. outer thing wouldn't work, so I suppose the choice would be either the two coils towards the bridge on each pickup vs. the two coils closer to the fingerboard on each pickup. Doesn't seem worth it to shift things up half an inch. May as well go with good old coil-splitting or series-parallel.

      Comment


      • #4
        Re: Wiring SH-1 vs. P-Rails

        Originally posted by RMosack View Post
        P-Rails are very different. The P-90 coil in each pickup are on the outside, and whether neck or bridge, always gets the green and red wires. In the neck, the P-90 coil is North. In the bridge, it's South. The inner rail coils always get the black and white wires. The rail is South in the neck and North in the bridge. Thus, from fingerboard to the bridge, the individual coils run North-South-North-South.
        AAAHH NO! The Rails coils are Green and Red! The P90's are Black and White. ALWAYS.

        I made it so that the bridge pickup matches up with our other bridge pickups. If you use it in place of any of our other bridge pickups, you can expect the same polarity. (same hum cancelling positions) if you wanted to use the P-Rails bridge with another of our neck pickups, and have inside/outside cancelling, you'd have to order an RWRP neck pickup, or at least a reverse polarity, and then switch the wires around yourself to create the equivalent of the reverse wind direction. But that's what you would have had to do with any of our other bridge pickups.

        If you use the P-Rails neck pickup with any of our standard bridge pickups, you will have inside/outside hum cancellation.

        To directly answer your question about a set of 59's or JB/Jazz set, you would need the RWRP neck pickup for inside/outsides to cancel. But be aware that many OEM's buy the set like that, and if you got the pickups used, or out of a factory guitar, the neck pickup may already be RWRP for this purpose.

        Comment


        • #5
          Re: Wiring SH-1 vs. P-Rails

          Originally posted by frankfalbo View Post
          AAAHH NO! The Rails coils are Green and Red! The P90's are Black and White. ALWAYS.

          Woah! Either the guy on the phone explained the wire colors totally wrong, or I took real bad notes! Either way, thanks for the clarification.




          Originally posted by frankfalbo View Post
          I made it so that the bridge pickup matches up with our other bridge pickups. If you use it in place of any of our other bridge pickups, you can expect the same polarity.
          By "matches up", my assumption is that you're talking about polarity only, not wire colors, right? You said the P-90s are always black and white. I assume that the bridge P-90 is the South magnet. In your wiring diagram for standard SD humbuckers, it shows the South magnet getting green and red.

          Comment


          • #6
            Re: Wiring SH-1 vs. P-Rails

            Originally posted by frankfalbo View Post
            AAAHH NO! The Rails coils are Green and Red! The P90's are Black and White. ALWAYS.

            I made it so that the bridge pickup matches up with our other bridge pickups. If you use it in place of any of our other bridge pickups, you can expect the same polarity. (same hum cancelling positions) if you wanted to use the P-Rails bridge with another of our neck pickups, and have inside/outside cancelling, you'd have to order an RWRP neck pickup, or at least a reverse polarity, and then switch the wires around yourself to create the equivalent of the reverse wind direction. But that's what you would have had to do with any of our other bridge pickups.

            If you use the P-Rails neck pickup with any of our standard bridge pickups, you will have inside/outside hum cancellation.

            To directly answer your question about a set of 59's or JB/Jazz set, you would need the RWRP neck pickup for inside/outsides to cancel. But be aware that many OEM's buy the set like that, and if you got the pickups used, or out of a factory guitar, the neck pickup may already be RWRP for this purpose.
            Sorry to dig up an old thread, but its still the top result when you google "P rails wire colors"
            Looking at http://www.seymourduncan.com/support...s_2v_2t_3w_2pp assuming up and down mean the same thing for both push/pulls; then when neck is up for P90, the red/white are shorted to black, so the red/green must be the P90. Likewise, when the neck is down for rail, the red/white are shorted to green (ground), so the rail must be the black/white.

            This would also make sense by the logic that the P rail is a direct replacement for a standard 4 wire bridge humbucker with the same wire codes and magnetic polarity (if you take the P90s to be equivalent to the screw coil in a HB, since they're both on the outside), while the neck has the same wiring but opposite magnetic polarity so that inner/outer can be hum-cancelling pairs when 2 pickups are used together (whether it's both P-rails or P-rail neck, HB bridge).

            In short, that wiring diagram seemsw to support RMosack over frankfalbo...

            That said, I'd like some certainty here as I plan to use a SHPR-1n in the neck position and an SH-1b in the bridge...

            Cheers,
            Matt
            Last edited by KX36; 04-10-2012, 09:30 AM.
            - KX36

            Comment


            • #7
              Re: Wiring SH-1 vs. P-Rails

              I would tend to believe Frank, since he just happens to be more familiar with P-Rails than anyone. And I mean anyone.

              It's been quite a while since I wired my P-Rails, but I seem to remember that black and white wires go to P-90 and red and green are the rail.

              Sometimes the diagrams can be misread since the pots are actually upside down. In which case: left is right and up is down.
              Originally Posted by IanBallard
              Rule of thumb... the more pot you have, the better your tone.

              Comment


              • #8
                Re: Wiring SH-1 vs. P-Rails

                Well I don't mean any disrespect to anyone, but his account doesn't seem to agree with that particular wiring diagram, so one of them must be wrong. I don't know about any other diagrams, but on that diagram, I can tell which way is "up" and which way is "down" on the HB/SC switch, and it's the fair assumption that it's the same on both switches in the diagram which led me to my post.
                - KX36

                Comment


                • #9
                  Re: Wiring SH-1 vs. P-Rails

                  Duncan diagrams do sometimes contain "typos". For example, that diagram you linked to shows the bridge push-pull wired backwards. (The bridge PP is in humbucker mode when its up.) Its likely the neck PP is the same.

                  This P-rails diagram also has a mistake in it. When rails are selected, the P-90 is left hanging, unterminated, on the "hot" side of the circuit, acting as a big noise antenna. The P-90 needs to be grounded out.

                  Comment


                  • #10
                    Re: Wiring SH-1 vs. P-Rails

                    Yeah, I did notice that the one I linked to says "tone push/pull is activated/does nothing", but there are only volume push/pulls there, so that's another typo.

                    Thanks for clearing that up guys... now if only someone would correct the wiring diagrams; they'll cause a lot of people like me confusion.

                    That said, I can't see a typo in the diagram you linked. The wiring is the same as in the Triple Shot and the function is the same. Basically it's just 2 halves of a series/parallel switch put onto separate switches, the coil split is just an effect of this and it works differently than a traditional coil split. While its true that when the red is shorted to black, the b/w coil is only connected on the hot end and while the white is shorted to green the r/g coil is only connected on the ground end, that's not a bug but part of the design and the only way to have coil taps as well as parallel operation. If the red was shorted to green (ground) as you suggest together with the white that's already shorted to green, you wouldn't get any sound when only one coil is split, as one coil is grounded while the other is floating on one end, and you wouldn't get parallel operation. [If you short across one parallel element, you short across all parallel elements, the only way to remove a coil from a parallel network is to lift one end of it. If you then take it when lifted and put it in the same place as the other is when it's lifted, you get the 2 in series. It's a really smart simple design which I quite like.] I also wonder if any noise from the antenna effect would actually cancel a portion of the hum from the active coil or add to it.

                    Here's a schematic I quickly drew for reference:


                    EDIT: Also, looking at that wiring diagram you sent, the volume push/pull shorts red to black, selecting the red/green coil only, and the description says the volume push/pull selects the rail coil, so that would suggest the rail is red/green and the P90 is black/white; which directly contradicts the wiring diagram I linked. ¬_¬ These diagrams seriously need to get sorted...
                    Last edited by KX36; 04-11-2012, 12:49 PM.
                    - KX36

                    Comment


                    • #11
                      Re: Wiring SH-1 vs. P-Rails

                      Originally posted by ArtieToo View Post
                      Duncan diagrams do sometimes contain "typos". For example, that diagram you linked to shows the bridge push-pull wired backwards. (The bridge PP is in humbucker mode when its up.) Its likely the neck PP is the same.

                      This P-rails diagram also has a mistake in it. When rails are selected, the P-90 is left hanging, unterminated, on the "hot" side of the circuit, acting as a big noise antenna. The P-90 needs to be grounded out.
                      Artie

                      Your "this p-rails diagram" link above doesn't work anymore, so I am not 100% sure which diagram you were describing, but I believe its the one below. Can you confirm? Mincer has started a sticky where we can identify diagrams that have some issues, so we can help improve the diagrams for everybody. Thanks. P.S. haven't seen any posts from you in a couple weeks - hope you're alright.

                      If that is the diagram you were talking about, then its current URL is: https://www.seymourduncan.com/wiring...-results-count

                      Click image for larger version

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                      Sanford: "The hardest part about tone chasing is losing the expectations associated with the hardware."

                      Comment


                      • #12
                        Re: Wiring SH-1 vs. P-Rails

                        Originally posted by Jack_TriPpEr View Post
                        Artie

                        Your "this p-rails diagram" link above doesn't work anymore, so I am not 100% sure which diagram you were describing, but I believe its the one below. Can you confirm? Mincer has started a sticky where we can identify diagrams that have some issues, so we can help improve the diagrams for everybody. Thanks. P.S. haven't seen any posts from you in a couple weeks - hope you're alright.

                        If that is the diagram you were talking about, then its current URL is: https://www.seymourduncan.com/wiring...-results-count

                        [ATTACH=CONFIG]104212[/ATTACH]
                        And if that is the diagram you were talking about, then this one would have the same issue, since it has the same wiring scheme except it incorporates 1 more volume control and 1 more tone control.

                        Click image for larger version

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Size:	58.3 KB
ID:	5818757
                        Sanford: "The hardest part about tone chasing is losing the expectations associated with the hardware."

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