EMG active pickups preamp circiut schematic.

[Dave Kerr]

Obviously with the Suhr system, the larger area of the coil makes up for the lack of a core.

Don't the tremelo block/bar/springs serve as a core for the Suhr system, or is the tremelo assembly off-plane enough to not have an effect on the inductance?

[David Schwab]

Don't the tremelo block/bar/springs serve as a core for the Suhr system, or is the tremelo assembly off-plane enough to not have an effect on the inductance?

It's not part of the system. The real system in built into the body, and loops around the pickguard. The trem version is a retrofit.

Here's the patent application:

#20050204905

[TGBoleyn]

Just curious, does that mean that you can wind the coils at different numbers, so long as you use an alnico in one and a ceramic in the other as a way to balance them out?

[Rick Turner]

Winding on ceramic is like winding an air core coil. Winding on a metal magnet...like Alnico...or on ferrous pole pieces changes the inductance as well as adding an eddy current factor. You could probably work up a pretty good match between a ceramic core and metallic core set of coils with different numbers of turns.

Note, however, the hoops (R/C networks) that Suhr uses to make the harmonic structure of induced hum match between the large Low Z coil and the single coil pickups. And not having looked at that recently, he must also do some kind of level switching to deal with positions 2 and 4 on the pickup selector switch. The center pickup IS NOT RWRP in that circuit.

Re. Alembic... The info presented here is not quite right. The very earliest guitars and basses...1971-'72 used a passive air (actually Plexiglas) core humcancelling coil that was identical in size, shape, and winds to the ceramic cored pickups. Then in around late 1972, we switched to the differential preamp design which used one humcancelling coil that was generally smaller than the pickup coils, and the induced hum was electronically subtracted after buffering. So we had three FET buffers (pickup, pickup, humcanceller) followed by the two op-amp differential preamps. Each channel had a gain control and a hum null trim pot.

[David Schwab]

Note, however, the hoops (R/C networks) that Suhr uses to make the harmonic structure of induced hum match between the large Low Z coil and the single coil pickups. And not having looked at that recently, he must also do some kind of level switching to deal with positions 2 and 4 on the pickup selector switch. The center pickup IS NOT RWRP in that circuit.

Re. Alembic... The info presented here is not quite right. The very earliest guitars and basses...1971-'72 used a passive air (actually Plexiglas) core humcancelling coil that was identical in size, shape, and winds to the ceramic cored pickups. Then in around late 1972, we switched to the differential preamp design which used one humcancelling coil that was generally smaller than the pickup coils, and the induced hum was electronically subtracted after buffering. So we had three FET buffers (pickup, pickup, humcanceller) followed by the two op-amp differential preamps. Each channel had a gain control and a hum null trim pot.

Rick, if you are referring to my post above, I'm talking about their newer stacked pickups. I based that on info they have posted at their website, and also stuff that Mica posted at their forums. Obviously I only know what I read, and who knows how accurate that is.

I have the series I and II preamp schematic, which is what you are talking about.

They seem to be quite different from the pickups you designed. I had a set here, as well as a set of Activator jazz pickups, and they read about 7-8K, which seems a lot higher than I thought the original pickups were. They are very low output too.

I'd love to hear more about the Series I pickups.