Neodymium, Variable Interstice Pickup Build (With Video)

Discussion in 'Luthiery, Modifications & Customizations' started by KhzDonut, Jul 30, 2019.

  1. KhzDonut

    KhzDonut Luthier, Gamer, Heretic

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    So I've been working on this project off and on for a couple years now (life has had a tendency of getting in the way)

    But I'm finally getting it dialed in to where I think I'm achieving the goals set forth.

    So here's a bit of a walkthrough of the current process, and a video demo of the latest prototype.


    My humble winding bench
    [​IMG]


    Laser cut Vulcanized Fibre/Forbon, fresh from Ponoko laser cutting services
    [​IMG]


    Parts for the humbucker laid out
    [​IMG]


    Example of the "layered assembly" process in action, which is a little bit of a chore but works out pretty well
    [​IMG]


    4-conductor wire installed, with a little window for soldering it to the bobbins from the backside, also polepiece access to attach little neodymium button magnets to each individual pole
    [​IMG]


    For this prototype I tried to create a faraday cage out of copper shielding tape, using some painters tape as an insulator. It worked reasonably well, but I really need to shield my control cavity, because I'm still getting some ambient noise. I'll figure it out.
    [​IMG]


    Bobbins assembled and ready for winding; 3,700 turns of 44awg wire on the south coil, 43awg on the north coil
    [​IMG]


    Bridge humbucker assembled. I'll probably change the design a little bit, because that little "heartbeat" is nearly impossible to bevel accurately by hand, which is a shame, I really like how it turned out, but holy crap what a hassle.
    [​IMG]


    And the neck pickup, which is a split coil design, similar to a Pbass pickup, with 8,000 winds of 43awg on the bass side, 44awg on the treble side.
    [​IMG]


    Installed in my self-built 7-string baritone (27" scale, tuned F#)
    [​IMG]


    And what you really want to know; how does it sound?
     
    IGC, Zhysick, neun Arme and 4 others like this.
  2. NickS

    NickS Rocket Surgeon

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    :agreed:

    Sounds really good, and looks great too!!
     
  3. Bearitone

    Bearitone SS.org Regular

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    Talk to me about the pole slants on the bridge pickup. Why do they diverge going from bass to treble? What were you hoping to accomplish? Did you achieve the desired result? Is this design specifically built around having neyodimium magnets or were you just trying neyo for fun?

    Oh and they look fucking awesome by the way!
     
    Solodini likes this.
  4. prlgmnr

    prlgmnr ...that kind of idea

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    I always get mixed up between "interstitial" and "intercostal"
     
  5. Defyantly

    Defyantly Aspiring Builder

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    These look freakin sweet! do you have any sound clips? how do they handle hi-gain situations?
     
  6. Erick Kroenen

    Erick Kroenen SS.org Regular

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    looks great, about the heartbeat could get confused with instrumental pickups, IMHO looks killer
     
  7. KhzDonut

    KhzDonut Luthier, Gamer, Heretic

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    The slant is to get a narrow sensing area under the bass side strings and a wider sensing area under the treble strings, the goal being a tighter, more focused sound on the low strings, and a more open and smoother sound on the high strings. I’ve flipped the pickup in the cavity to compare the sound, and while it’s a subtle effect, it is readily apparent when A/B’ing the recordings.

    I chose neodymium because they come in little button sizes, in a variety of strengths and sizes, so I can really fine tune the magnet strength (I could even tune the strength per-string if I wanted, similar to staggering the poles on a strat pickup, but that would really be hard to do in a way that would fit every single player and their preferred string gauges)

    The other problem was that typically a humbucker used a bar magnet, and that wouldn’t work in this situation because the poles are not evenly spaced across the width of the pickup.

    I tend to prefer ceramic magnets because of the bright, ringing high-midrange tones, but I find the neodymium to be very percussive and punchy in the lows, so for this application they work very well.


    The last image in the original post should be an embedded YouTube video, but if you’re having trouble viewing it you can go here:

    https://youtu.be/Wqn1-DTVPzY


    I’ll take that into consideration if I ever put these into production or anything like that, I definitely don’t want to step in any toes with trademarks or anything. Thanks!
     
    Ribboz and Erick Kroenen like this.
  8. Xk6m6m5X

    Xk6m6m5X SS.org Regular

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    Dude....you need to patten and market these, i love this idea, the designs is KILLER if i wasnt so fucking broke id deff buy a pair if you were taking orders
     
  9. Fretless

    Fretless Knob Fiddler

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    How's the string pull from the magnets? I love using neo magnets in my designs, they're fantastic, but string pull is something I spent months designing ways to work around.
     
  10. KhzDonut

    KhzDonut Luthier, Gamer, Heretic

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    I find that it’s a fine line between the magnet being too weak and sounding kind of thin, and being too strong and losing sustain. Also matching the magnet size to the pole piece seems to be a factor, but I need to test that a little more to see if that was just a function of magnet strength.

    Going off the numbers from KJ magnetics, seems like the sweet spot is somewhere around 1lb of pull strength per magnet, maybe a bit less, depending on pole size. If it’s a solid 1/4 pole, longer than 3/8”, I was getting away with a bit stronger before major dampening seemed worse than, say, a Duncan distortion pickup.

    Doing a gauss reading on pole pieces doesn’t seem to give me usable/comparable results, so I’ve just been doing trial and error finding the right magnets.

    Do you have any clips or anything of your designs? I’d be interested in your results if you were willing to share
     
  11. Fretless

    Fretless Knob Fiddler

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    I don't have any samples currently, no, I'm no where near good enough on guitar to demonstrate what these pickups are capable of, and I haven't gotten around to recording bass sample yet. My design is also quite a bit different than yours too, although I'm not sure how much I can willingly share since I manufacture these for another company commercially. I don't want to get in trouble for advertising either haha.

    One thing I can say is that my proximity from the magnet to the string is far enough to where I'm not able to discern any significant impact on string sustain.

    Initially I was thinking you were using the magnet purely as the pole piece, but since you said you're not, I'm sure it's not as big of an issue. I use magnets that are quite a bit stronger than what you use(I have designs that use between 4-6lbs of pull force per magnet)
     
    Winspear likes this.
  12. KhzDonut

    KhzDonut Luthier, Gamer, Heretic

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    Yeah, I've got steel pole pieces (not sure what alloy) I have some designs I haven't built yet that use really thin Neo magnets as polepieces, but that's a ways out.

    I'm surprised 4-6lb of pull force works, I haven't tried anything that high. Is that for bass?
     

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