Need help understanding an RC high-pass filter

[McCreed]

Using 500k pots.

I also have seen a Seymour Duncan diagram with a single .047uf cap in series with the hot lead of the HB going to the switch(or volume pot), but not tried it.

SD w/ .047uf cap

[Simon Barden]

That .047 uF looks wrong to me, as you’d get a 7 Hz filter point as it must take the pot resistance into account. 0.0047uF/4.7nF should give a 67Hz filter point, which would be more useful, but maybe the pickup inductance also comes into play here. 7Hz is the typical DC blocking cap filter frequency on an FX pedal input stage.

With passive electronics, everything affects everything else. Add in some semiconductors or valves to separate the stages and you’ve got far more control over what’s going on.