Here is an interesting video by the channel DylanTalksTone.
Dylan cut in half a Fishman Fluence guitar pickup. These pickups have coils that are made using PCB traces. There are something like 26 layers for each of the two coils, and each layer contains a spiral of around that same number of windings.
The exposed copper ends in the cross-section make up a rectangular grid where you can count the rows and columns visually.
Around 7:04 is where the first shot of the cross section is shown.
It is way fewer windings than in a traditional passive pickup. By itself, the signal transfer would result in a very trebly, tinny tone. The active circuitry does all the tone shaping to get various pickup sounds.
The PCB process ensures a lot of consistency. The traces look wide enough such that the DC resistance of the coils is negligible and the accuracy of the printed circuit should produce a very consistent inductance from one unit to the next. Plus at such a low inductance, it won't even matter.
Could not agree more! And yes, though due to the lack of specifications available for the ferrite rods I purchased, it ended up being more of a calculation of their permeability based on the measured inductance. I'll have another post soon that shows measuring the resonance frequency of these inductors with various types of capacitors, which is a fun exercise in parasitic capacitance and inductance.
Dylan cut in half a Fishman Fluence guitar pickup. These pickups have coils that are made using PCB traces. There are something like 26 layers for each of the two coils, and each layer contains a spiral of around that same number of windings.
The exposed copper ends in the cross-section make up a rectangular grid where you can count the rows and columns visually.
https://www.youtube.com/watch?v=9Uih75f4now
Around 7:04 is where the first shot of the cross section is shown.
It is way fewer windings than in a traditional passive pickup. By itself, the signal transfer would result in a very trebly, tinny tone. The active circuitry does all the tone shaping to get various pickup sounds.
The PCB process ensures a lot of consistency. The traces look wide enough such that the DC resistance of the coils is negligible and the accuracy of the printed circuit should produce a very consistent inductance from one unit to the next. Plus at such a low inductance, it won't even matter.