Post by ms on Dec 19, 2018 7:13:38 GMT -5
guitarnuts2.proboards.com/thread/7834/impedance-measurements-computer-interface-unit discussed a simple series model, among other things. It also discussed some odd effects that occur at high frequencies that can complicate things. Another "complicated effect" is caused by the baseplate if you try to reduce electrical noise pickup by grounding it. Attached are two impedance measurements of an SD SH4. This is a very high impedance pickup, and so it is especially susceptible to capacitive coupling effects.
The difference between the two is that the second one with the funny bump at high frequencies is that the baseplate is connected to the pickup wire that gets grounded, but it floats in the other.
With the base plate grounded the two coils capacitively couple to it very differently because one coil is closer to ground than the other. (Even with the plate floating there probably are minor differences.)
The significance of this for pickup modeling is that the model would have to be quite complicated if you want to allow for this. I have not; the curves with the C removed are wrong in the grounded case because the model used does not have the additional capacitors.
So two coil pickups with the coils in series are not always as simple as we would like.
The difference between the two is that the second one with the funny bump at high frequencies is that the baseplate is connected to the pickup wire that gets grounded, but it floats in the other.
With the base plate grounded the two coils capacitively couple to it very differently because one coil is closer to ground than the other. (Even with the plate floating there probably are minor differences.)
The significance of this for pickup modeling is that the model would have to be quite complicated if you want to allow for this. I have not; the curves with the C removed are wrong in the grounded case because the model used does not have the additional capacitors.
So two coil pickups with the coils in series are not always as simple as we would like.