Hi Bert,
The Technics Volume Pedal uses a nominal 20K Ohm potentiometer.

The extremities of the pot. are connected between the Tip and Sleeve of a 1/4 inch Stereo jack plug, and the Slider of the pot. is connected to the Ring (Middle) connector of the jack plug.

The Tip and Sleeve connections should be arranged in such a way that when the pedal is fully depressed, the resistance between the Ring and Sleeve of the jack plug is minimum. See the attached diagram......