Just thinking in public...

[Mike Sulzer]

... does the string need to be magnetized?

Yes. You have to look at the physics: how can a steel string affect a magnetic field? The only way is for the atomic currents in the steel to become partially aligned by the applied field, the degree of alignment being dependent upon the strength of the field.

This alignment is magnetization, and it creates a magnetic field which adds to the applied field. In fact, the field produced by the magnetized string is the only one that matters for inducing voltage across the coil. The steady field from the magnets does not induce the voltage in the coil. It is the changing field from the vibrating string, passing through the coil, that creates the voltage. Each loop of wire has a voltage induced around it that depends on the rate of change of flux (field times area) inside it.

[Chris Turner]

Here's what it looks like in the real world:


Instead of a solid blade-like ferrous core, out of laziness I used four metal dowel pins. So under each string, from center outward, there's a central metal slug, coil surrounding that, then two 1/4" by 3/4" neo magnets. If I made another, I'd actually use smaller magnets to decrease the pull on the strings (probably go with 3/16" X 3/4"). Maybe even just offset each one so they're not directly under the string.

It's got 7500 turns on it, and the impedance measures ~5.6 K. I didn't pot it, as I just wanted to see how it sounded, and honestly didn't expect much.

Sounds pretty good, I think. I'm kinda surprised.

[Chris Turner]

...and here's a sample of what it sounds like (in the neck position of my SX Jazz bass):

[frankfalbo]

Before George Fullerton passed, he had Seymour make him this design, but with a bar on each side (so like a blade in place of your poles) I don't know what the outcome was, I'm sure there are some confidentiality issues, but who knows, maybe someday we'll see something on a G&L and we'll say "oh, that's what it was".

There are all sorts of ways you can bring these legos together. Even if something was considered a failure by previous embodiments there's almost always something of value there. If you see an old design and say "that procedure didn't work because it sucked away tons of top end" then there's always the chance that a little bit of that idea can be incorporated when you're working on a new idea that's too bright, etc.

[Bruce Johnson]

When it comes to pickup design, you should never listen to anyone's advice.