TC – is a 250KΩ tone potentiometer with an option of choosing 4 different capacitors, or the combination of them, with the consequence of different »depth« of the tone control activity.
There are 3 jumper swithes on the circuit board. In the first picture they are all OFF, meaning there is just a basic capacitor acting on a tone control -the brightest sound.
In the second picture all of the 3 jumper switches are ON, meaning the tone control is acting with maximum capacitance – the deepest sound.
Choose the jumper switch combination for your optimal sound.