What does this pot do?

[Tom Bradshaw]

I obtained a rather old Ernie Ball volume pedal. It has a potentiometer on the right side of the base section of the pedal. It is connected to the actual volume potentiometer in some kind of hookup. Wires leading from it go to each of the pin lugs on the output jack and the input jack. Between these two lugs is also a small capacitor. Can anyone tell me what this potentiometer is supposed to do? At the moment it seems to have no impact on the volume control, regardless of whether it is turned on or off. I am thinking it is supposed to be a taper control, but I'm not sure since it doesn't seem to do anything. Perhaps it is designed to be a tone control, but it does't seem to alter the output tone of an instrument in any manner. The pot doesn't seem to be damaged and an ohm meter reveals that it is working by moving the needle in the ohm meter.

Does anyone know? ...Tom Bradshaw