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Thread: Split coil HBs - noise cancelling pair?

  1. #1
    Supporting Member Steve A.'s Avatar
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    Split coil HBs - noise cancelling pair?

    I believe that PRS was one of the first companies to mass-produce guitars with noise cancelling pairs of split-coil humbuckers. (They also gave you a choice between inner and outer pairs.) As I recall they accomplished that by reversing the magnet and coil wires in one of the pickups. I'm checking here for confirmation of that...

    BTW the PRS SE pickups I've seen are not like that and both pickups have the same magnetic polarity and winding direction. None of the PRS SE guitars I've seen have split coil switches so that is not an issue for them...

    I have a set of PRS SE245 pickups that I want to rewire with 4 conductor cable similar to what SD and DiM, et al, use. Any suggestions for an on-line source for that with reasonable shipping charges that sells the cable by the foot? I bought some in the past but forget who the seller was...

    BTW the PRS SE245 pickups are really nice and very reasonably priced on eBay; I've bought a few sets of pull-outs to replace the 490/498 pickups in my Gibsons — for under $50 including shipping.

    With ALL of my other PRS SE guitars it was mandatory for me to either replace the pickups or change the magnets from A5 to A2 to make them smoother and sweeter. (In retrospect, I think I should have left the neck HBs alone since they are less prone to muddiness with A5 than A2.) The PRS SE P-90's with an A2 magnet swap sound almost as good as boutique pickups, at least the ones in the Soapbar II's I bought 10 or 12 years ago.

    Thanks!

    Steve Ahola

    P.S. There is a quick'n'dirty way to get noise cancelling when splitting the coils of a pair of hbs with identical polarity and winding direction: for one of the pickups run the two middle leads to HOT(+) rather than to ground.

    I don't like the concept as you have one coil with both leads connected to HOT(+) which undoubtedly must add some noise to the equation but it didn't seem to be a problem in LPs with a shielded control cavity (I'll have to recheck that to be sure.)
    Last edited by Steve A.; 05-08-2017 at 09:48 PM.

  2. #2
    ToneOholic! big_teee's Avatar
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    You can do the inside out, outside in wiring method, with 4 wire pickups.
    http://music-electronics-forum.com/a...g.-blend-2.jpg
    You can see how it works, by following start and finish leads of each pickup.
    I got the idea from the Trey Anastasio's guitar wiring layout.
    Trey Anastasio's Guitar Wiring
    The amount of pots, and blend are optional.
    T
    Technicians Run the World, but Bankers, Lawyers, and Accountants, Take All The Credit!
    Keep Rockin! B_T
    Terry

  3. #3
    Supporting Member Steve A.'s Avatar
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    Quote Originally Posted by big_teee View Post
    You can do the inside out, outside in wiring method, with 4 wire pickups.
    http://music-electronics-forum.com/a...g.-blend-2.jpg
    You can see how it works, by following start and finish leads of each pickup.
    I got the idea from the Trey Anastasio's guitar wiring layout.
    Trey Anastasio's Guitar Wiring
    The amount of pots, and blend are optional.
    T
    The whole Trey Anastasio Guitar Wiring site at 1728.com going back to 1999 is amazing! I would like to add a phase switch on a third P-P pot for my brand-new Mitchell MS400*** w/2V & 1T based on the page you posted.

    As for your own drawing is there a thread here that explains exactly what it does? It looks very interesting!

    Steve A.

    P.S. Any suggestions for a source of good 4 conductor cable for humbuckers (in lengths less than a full spool.) I'll see if I can find my previous source in my eBay order history on-line.

    *** The black version of this guitar is currently on sale for $249.99 (as of 05/09/2017) IMO the best bang for buck deal on a new electric guitar EVER.

    OT: Mitchell has been the house brand for GC/MF for years and their brand new line of electrics is amazing, with the MS400 modern singlecut being a step up from the similar PRS SE offerings on sale at less than half the price with these features:
    - individual volume controls
    - locking tuners
    - beautiful binding on body and neck
    - great pickups (comparable to PRS SE245 pups, the first G&B imports that I haven't wanted to upgrade)
    - through-body strings
    - has p-p coil cut switch for both pups on tone pot
    - most important, this guitar plays like a dream right out of the box! This is true for the all of the ones I've played extensively (I bought 4 of them but returned 2 of them.)

    CONS:
    - The output jack is in an angled recessed opening facing the bottom strap button. With a straight plug you need to put guitar in stand as it will tip over otherwise. Very easy to rewire with a normal jack plate using a forstner bit.
    - the pots are not mounted perpendicular to the carved top but to the flat back. Very noticeable shadow when engaging the otherwise stunningly beautiful Honey Burst model on sale for $299.99.

    Mitchell MS400 Modern Single-Cutaway Electric Guitar | Guitar Center
    Last edited by Steve A.; 05-10-2017 at 12:05 AM.

  4. #4
    Member PeterPan's Avatar
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    Back when I was playing Jazz on an acoustic, I always preferred the sound of a magnetic pickup in the hole. After years of being plagued by unwanted noise in clubs (hard to compete with 10,000 volt neon sign transformers), I finally built my own dual coil vertically stacked pickup in a metal shell, running the two outputs to a high-Z differential configured OP-AMP right inside the shell, with two trim-pots for level and balance. Because of the stacking, of course only one picked the string sound, and the controls were available through tiny holes in the front. The next time I was in a club and started to hear that annoying hum pickup, I pulled out my little screwdriver and literally "nulled" out the hum. It was a pain in the butt to build, and of course it meant feeding power to my circuit. But I believe I now have the quietest solution I've ever had, and have the benefit of a single coil sound in an acoustic.

    Who knows... maybe this will spark an idea for what you want.
    Steve A. likes this.

  5. #5
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    http://https://www.aliexpress.com/wh...=Hookup+4+core

    The quick and dirty way you mentioned is the only correct one. No hum added. The more complicated way would be switching the output from the hot lead to the centre leads, which would leave the unused coil still connected with one lead to the output, other lead disconnected - makes a great antena. You do not want this. Shorting the coil center to HOT is better.

  6. #6
    rjb
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    Quote Originally Posted by kmensik View Post
    The more complicated way would be switching the output from the hot lead to the centre leads, which would leave the unused coil still connected with one lead to the output, other lead disconnected
    There is (almost) always more than one "correct" way.
    The "more complicated" way referenced in post #2 shunts both the Neck "North" coil and the Bridge "South" coil to ground.

    Quote Originally Posted by kmensik View Post
    - makes a great antena.You do not want this. Shorting the coil center to HOT is better.
    There are always tradeoffs in life.
    Some say that a more "authentic" single coil sound is produced by floating, rather than shunting, a coil.
    Why? A shunted coil still produces a current around the closed loop.
    You can convince yourself by imagining the pickup modeled as a signal generator in series with a resistor and an inductor.
    The signal in the shunted coil induces a signal in the "active" coil, in transformer-like fashion.
    You can verify this by tapping on a shunted coil with a screwdriver.
    Or so I've been told.

    -rb

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    Yes, it feels weird to short a generator, but it is high impedance voltage source with almost no current. So it is better not to keep it floating. I tried to hear the difference with no success.
    You hear the tapping because the other polepieces are also in the magnetic field of the active coil. That transformer action is present, but to very little effect. I also tried to put a loop of thick wire around the working coil to simulate a real short with some current flowing in it, could not hear any difference. Some Duncan HB pickups have a loop of foil around each coil with ends soldered together and grounded. It should affect the pickup a lot, a good manner is to keep the loop open. But it works nicely as shielding, so such a split coil is even quieter than a traditional single coil, and affects the tone of the pickup less than a brass cover, to my ears at least.

    I wired my H+H guitars with two push-push switches. One splits both humbuckers, the other is out-of-phase switch. In single coil mode, both in-phase and out-of-phase positions are hum cancelling, which is funny and a little harder to imagine.

  8. #8
    rjb
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    Quote Originally Posted by kmensik View Post
    I tried to hear the difference with no success.
    I don't have "golden ears" either; just relaying what I've read....

    Quote Originally Posted by kmensik View Post
    You hear the tapping because the other polepieces are also in the magnetic field of the active coil.
    I'll buy that.

    Quote Originally Posted by kmensik View Post
    I wired my H+H guitars with two push-push switches. One splits both humbuckers, the other is out-of-phase switch. In single coil mode, both in-phase and out-of-phase positions are hum cancelling, which is funny and a little harder to imagine.
    That works if you do the phase flip "before" the coil split.
    Say the neck pickup goes to the OoP switch, then to the "split" switch- which shunts neck "coil A" when in-phase.
    Now flip the OoP switch; the "split" switch will now shunt neck "coil B".
    Easy-peasy.

    -rb
    Last edited by rjb; 05-31-2017 at 04:10 AM.

  9. #9
    rjb
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    I see a bunch of offers for White/Black/Red/Yellow with served shield, and one for White/Black/Red/Green with what appears to be about 40% coverage braided shield. All Chinese made, no specs given for anything.

    For U.S. customers, better price and quality here:
    (EDIT: Plus free shipping.)
    https://www.markertek.com/product/mg...per-foot-black

    IIRC, most MEF pickup "pros" get their cable from WD or Mojotone.

    -rb

    PS: It occurs to me that it might seem like I'm attacking you. I just have no sense of tact.
    Last edited by rjb; 05-31-2017 at 06:23 PM.

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    No way, it is a constructive talk.

    Phase before split, that is the trick.

    I hate cables of plain non-tinned non-silvered copper. In Europe I buy this cable
    https://www.thomann.de/cz/goeldo_pic...f=search_prv_3
    Decent quality, foil + braid shielding, relatively expensive.
    Sometimes I make my own pickup cable. Perfect braided shield from a UHF or video cable, four leads from some good printer cable or USB cable, and you're one step above these commercial cables, plus with the vintage look. You can always add thin heatshrink tube over it, if you want it isolated.

  11. #11
    rjb
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    Quote Originally Posted by kmensik View Post
    https://www.thomann.de/cz/goeldo_pic...f=search_prv_3
    Decent quality, foil + braid shielding, relatively expensive.
    In USD, $3.74 plus $16.85 shipping for a meter of cable?
    Yikes!!!

    -rb

  12. #12
    Member PeterPan's Avatar
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    Quote Originally Posted by Steve A. View Post
    I don't like the concept as you have one coil with both leads connected to HOT(+) which undoubtedly must add some noise to the equation but it didn't seem to be a problem in LPs with a shielded control cavity (I'll have to recheck that to be sure.)
    This may be irrelevant, but I figure its always best to mention possible caveats. When I rewired my LP mini-humbuckers for switchable single/dual mode selection, I also thought of shorting the "unused" coil for single mode, but I decided not to. It seemed to me if I have strings in the field of a pickup and I short that pickup, it would have to dampen the string vibration and decrease my sustain. The pickup, after all, is an unloaded generator. So if you short it, it is like a generator with maximum load. So it would seem the energy to "drive" that load would have to come from the strings, effectively acting as drag. I never proved out whether this would be much of a problem, but it seemed this could be a factor. I also have the metal shields grounded and intact, so the noise might not be a factor. BUT to be on the safe side I do remember switching the ground point rather than the HOT, so that the only thing "floating" would be the coil that is grounded at its other end anyway.

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