Swapping magnet material - Inductance effect?

[AdmiralB]

I don't wind, or own the requisite gear to do this myself, but I'll bet someone here does and has.

What, in very general terms, would the impact be on inductance when swapping one magnet type (ferrite v. alnico, say)?

I'm specifically thinking about P90/humbucker type bars. Let's say I've got a P90 with the standard 10000 turns of 42 and two alnicos. That's usually what, somewhere around 5.5H?

If I swap the magnets for ceramic, inductance will decrease, but by how much? 1H? More? Less?

If Duncan published inductance, I could work this out from their data points, but I don't know of any pickup maker who 1) offers otherwise identical pickups with different magnet materials, and 2) publishes inductance data.

[big_teee]

Seymour duncan shows higher than that.
Antiquity P-90 "Soapbar": neck and bridge black cover / 11034-61 & -62 - Seymour Duncan P-90 Guitar Pickups
Swapping to a ceramic magnet will increase the gauss, I would think it would increase the Inductance.
Ceramics have less eddy currents, so not sure about the induuctance difference, but someone here can answer that.
Ceramics generally have a brighter harsher tone.
T

[ScottA]

In a PAF or P90 type pickup, the magnet is external to the core, so the effect of the electromagnetic properties of the magnet will be much less significant on the inductance of the pickup than if the magnet were the pole piece. The steel pole pieces in the core, along with the windings, are the primary driver of the inductance level in this type of pickup.

I would think you would see a drop going from more permeable AlNiCo to less permeable ceramic, but it would be more on the order of a couple of percentage points, certainly not 1 full Henry. AlNiCo 5 is only slightly more permeable than ceramic, AlNiCo 2 is the most permeable AlNiCo alloy I've measured.

[AdmiralB]

Thanks for that, I didn't realize they published any inductance data. Only on Antiquities, it seems.

Ceramic should reduce inductance, but I don't know by how much.

[AdmiralB]

Much obliged!