The cap in question is part of the guitar’s tone circuit, which along with a potentiometer forms a variable low-pass filter. A rich folklore has developed over the years around these circuits ...

Signals with frequency above or below the filter’s passband will be attenuated. The band-pass itself is constructed from a high pass and a low pass filter. [Ryan] used simple resistor capacitor ...

While the 2045 filter has just a single low-pass mode, the R-8 can be run in low-pass, band-pass, high-pass and notch configurations. When the two filters are combined you get three additional ...