A Q for the pros...

[David Schwab]

Thanks to all for great responses.

I would love to hear more about eddy currents in pickups. I've a vague idea about heat losses and ineffeciencies in transformers etc (I believe laminated formers are used to help in this area) but I can't get my head around how they apply to guitar pickups. Chris Kinman even has a design with a laminated bobin for the hum cancelling coil. And lace's new pickups onlyhave a tiny coil that looks like a mini transformer at one end.

Eddy currents are currents induced in metal surfaces by nearby magnetic fields. The currents swirl around on the surface like eddies, and create their own magnetic fields that oppose the field that created them.

In pickups this can dull the tone.

The laminated cores in transformers and pickups help by not having a very thick piece of metal. Thin pieces have less issues with eddy currents and another way around the problem is to break up the surface area.

Kinman's idea is to use a steel bottom bobbin to increase the inductance of the dummy coil, and the laminations help prevent eddy currents.

Some pickup makers use laminated steel blades in their pickups to help prevent treble loss.

The Lace pickups (I assume you mean the Alumitone) do have a transformer. They are single turn coils, and produce more current than voltage. The transformer steps the output up. In the Alumitones, the aluminum structure that forms the pickup is actually the coil. The two black squares are ceramic magnets. In the Transsensor pickup, they have a thick single loop of copper.

This is similar to ribbon microphones. A thin ribbon of metal is hung in front of a magnet, and has a wire attached to each end. When the sound vibrations move the ribbon, the magnet induces current to flow in the ribbon.

[David Schwab]

D. Schwab listed a few tapes that he uses.

I kind of use what I have on hand at the moment. I've used Scotch "magic" tape, white paper tape, black electrical tape, and black paper tape like you use to wrap coils.

I usually wrap it so it bends over onto the flatwork a little. Keep in mind that I'm wrapping it around a bar, not rods. Shouldn't matter though.

I recently wound three bass humbuckers, and all shorted out except one of the coils. When I cut the wire off to rewind them I realized I did tape that one coil, and forgot the others! I used Scotch "magic" tape on that one.