Poly wire vs Plain Enamel in J-Bass

Discussion in 'Guitar Demo Videos and Soundclips' started by Ron Daniels, Jan 21, 2015.

  1. Ron Daniels

    Ron Daniels Member

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    Jan 5, 2015
    Location:
    Kitchener, Ontario Canada
    I have a friend who knows I dabble with making pickups and guitars. About a month ago, he asked me if I could take a look at his bass. The front pickup had stopped working.

    Sure!

    There was an open circuit somewhere in the coil, so the only 2 solutions were replace it or re-wind it. So... I rewound it with the 42 AWG poly I had on hand, wax potted it and got the bass working quite nicely...

    Then... we looked on eBay and found out what a '73 Fender J bass in natural Ash is worth. On second thought... I'd better get some 42 AWG plain enamel wire in and bring this thing back to its original spec's.

    Which I did today. I didn't get it lacquer potted due yet to the fact that the nearest can is a 3 hour return drive, but it's a tight enough coil that there's no feedback issues anyway.

    Here's a video of what I did to it (take the JD Custom branding with a grain of salt... I'm still experimenting with whether I'll try to launch an actual business around making pickups/guitar electronics) today:

    http://youtu.be/Rt7izvD2c4U

    I play the same riff with the same settings with both the poly wire and the plain enamel. I definitely hear a difference, even though the winds are only 100 ohms apart.

    Enjoy!




    Ron
     
  2. GCKelloch

    GCKelloch Member

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    Jan 19, 2015
    It's not the wire that sounds different. There's a lot of misconception about what affects pickup sound. Copper wire is wire is wire. Thinner wire does have higher Rac at higher frequencies, so the pickup would have a little less highs for the same inductance value. Steel or silver might possibly sound different at very high frequencies, because the surface to core AC reactance is different, but it's not an issue for electric guitars. A less than ~10% wind-count variance is hardly noticeable, and can easily be compensated for via the external component load. ~100 ohms is entirely insignificant compared to ~8k.

    Off hand, it sounds like the pickup height is slightly lower in the second example. Even ~1/4 a screw turn is enough to change the string timbre. That's what happens when you adjust the pickup height. The balance of low to high harmonics for each note changes – that's string timbre. Closer sounds fatter/sweeter as the fundamental ratio raises, but some pickups change timbre more significantly than others depending on the coil-size/dimensions, and the magnetic field distribution in the string area above it.

    Regarding PE wire: The winding instructions for original PE wire required that the pickup be heated to 125d C shortly after winding. PE has a tendency to crack around the bobbin corners. The heat treatment patches the cracks guarding against high internal C values and/or eddy-current shorts. Poly wire tends to stretch, raising internal C. There's no way to ensure against exceeding specified wire tension when hand-winding, so the wire may stretch a little anyway, but the PE post heat treatment method is probably the best for hand-winding, and will deliver the best highs. A 42AWG 8k AlNiCo core pickup should be ~4H, so you'd need a pretty low C cable to get smooth extended highs. I'd recommend ~200pF, or even lower. If the pickup has high internal C or any type of internal shorts, the highs may be compromised anyway. You would need to get organic lacquered PE wire, rather than some artificial variant. “Plain Enamel” is rather nondescript. Thicker insulation also reduces internal C, but makes the coil unnecessarily larger, so finer wire is actually the best solution. Proper annealing also helps keep the wire shape consistent around corners. Elektrisola should have the right stuff.
     
  3. Ron Daniels

    Ron Daniels Member

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    Jan 5, 2015
    Location:
    Kitchener, Ontario Canada
    Thanks for the great feedback and good advice about the annealing process. Since the pickup isn't potted yet. I'll anneal it for a while before I pot it. How long would you recommend, and how slowly would you bring it back to room temp?

    Would I need to "re-zap" the alnico magnets afterwards?

    Do you think there's any tonal difference between coating materials if the thickness of the coating is the same?




    Ron
     
  4. GCKelloch

    GCKelloch Member

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    Jan 19, 2015
    Wire normally comes already annealed. How stable the wire is under tension depends on the annealing. I don't know more than that about it. I was talking about heating PE wire shorty after winding to patch any insulation cracks. It needs to be done within a few hours of winding with the right kind of wire. So even if it is the right wire, it's too late. Elektrisola has several kinds of wire with heat bonding insulation. You should ask them what they'd recommend for your purpose. Once you get the right wire, I'd just drop the newly wound pickup in a wax bath heated to 125d C or whatever is recommended for the wire. Someone at Elekrisola should be able to help you. 125C should not be enough heat to affect the magnets. You should be able to find out the heat limits of the magnets you buy at the site you get them from. That's all I know about it.

    Wiring insulation material would only cause a difference regarding it's ability to insulate. Less insulation means potentially higher internal capacitance (and maybe other losses I am unaware of), which reduces the high end response for a given pickup inductance.
     

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