Push-pull mod but in 50s wiring?

[marcello252]

Hey Artie & Marcello, really not sure my contribution is needed but I agree with what Artie said : the knee frequency is set by the value of the tone cap + the inductance of the pickup. And the value of the tone pot defines the amplitude of the resonant peak (itself set by the inductance of the pickup + capacitance of the whole wiring)...

do you have an equation for q and f please ? the classic first order RC filter comes to my mind but being there a L it's a a bit complex, it's a second order I think

[freefrog]

To know at which frequency a pickup resonates when paired to a tone cap or not, I'd just use the following tool (under the basic equation that I was about to share):

https://www.petervis.com/Radios/parallel-tuned-circuit-calculator/parallel-tuned-circuit-calculator-f.html

To know the resonant frequency once the tone pot at zero, enter the inductance of your pickup (example: 2H for a CS69 single coil, 4H for a P.A.F. clone) then set C @ 0.022 Farad or whatever tone cap value you want .

To know the resonant frequency with pots full up, keep the inductance of the pickup and just set C much lower to reflect the parasitic capacitance of the pickup itself + its pots and wires + the guitar cable used (example: 100pF of coil(s) + 20pF of wires + 10pF per pot and jack plug + 450pF from guitar to input).
The resistance of the pots will change the height of the resonant peak but not really the resonant frequency (at least with the kind of resistive loads most often present in parallel with pickups).

There are various ways to know the Q factor and when it comes to guitar pickups, it's most often calculated @ 1000hz but I find the related equations rather indifferent if not misleading, personally. To avoid any petty post about that, let's just share a link toward a reliable doc with further explanations:

https://www.gitec-forum-eng.de/wp-content/uploads/2019/03/poteg-5-5-4-resonance-q-factor.pdf

HTH. :-)