This bass and treble controller circuit is based on the classic Baxandall tone control circuitry and provides a maximum cut and boost of around 10dB at 10kHz and 50Hz.
The first stage that is built around BC109C transistor acts as a buffer and provides the circuit with a high input impedance at around 250kΩ. The gain of the stage is nearly unity.
Since the Baxandall tone control circuit is a passive design, all frequencies are amplified. The position of the boss and treble control potentiometers and reactance of the capacitors affect the audio response.
Second BC109C transistor provides about triple boost. The potentiometers should be linear type. The output of the circuit can drive an amplifier with input impedance of 10kΩ to 250kΩ.