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Guitar Pickup Explorer

A passive guitar pickup is a coil, a resistance and a little capacitance, loaded by the volume and tone pots, the cable and the amp input. Drag the controls and watch the frequency response change. The curve shows the output at the amp input relative to the voltage induced in the coil.

Current String fundamentals, low E to 24th fret
Hover or touch the plot to read a value.
Resonant peak
Peak height
Bump vs 100 Hz
Level at 1 kHz

Circuit being calculated

EMF L coil R coil C wind tone C tone vol top 1 nF vol bottom cable amp in out

Same model as the LTspice netlist pickup-tone-cable.cir, extended with the volume pot as a voltage divider. Pots use an audio (log) taper: at knob position 5 the resistance is about 10% of the full value.

Things to try

  • Roll the tone knob from 10 to 0. The peak moves down and flattens: the tone cap adds to the coil's resonance capacitance once the tone pot resistance gets small.
  • Keep a reference, then change the cable from 1 m to 6 m. The peak drops in frequency because cable capacitance is in parallel with the coil.
  • Set volume to 7 and compare with 10. The pot's top section adds series resistance and the highs fade. Then enable the treble bleed cap.
  • Load the Jazzmaster preset, keep it as reference, then switch it to 250k pots. The 1M pots of the classic lead circuit barely load the coil, which is part of the Jazzmaster's bright, airy sound. The separate rhythm circuit is not modelled.
  • Switch between 250k and 500k pots on a humbucker. Higher pot values damp the resonance less, so the peak gets taller.
  • Drop the amp input to 100k, as some pedals with low input impedance do. That's why a buffer or a 1M input matters.