This circuit is a circuit diagram preamp and tone controls are combined in a single series. Series preamp and tone controls are using the transistor as a control. In the picture below P1 to control the volume level, to control the level of P2 and P3 for Bass control Treble level. This circuit is a circuit diagram mono channel, built a similar circuit to make this circuit stereo. The following is a schematic drawing: Component: R1__________220K R2__________100K R3__________2K7 R4 R5_______8K2 R6__________4K7 R7, R8, R13___2K2 R9__________2M2 R10, R11_____47K R12_________33K R14_________470R R15_________10K R16_________3K3 C1, C2, C9____470nF 63V C3, C4_______47nF 63V C5, C6_______6n8 63V C7__________10?F 63V C8, C10______22?F 25V C11_________470?F 25V Q1, Q3_______BC550C Low noise NPN 45V 100mA High gain TransistorsQ2__________2N3819 General-purpose N-Channel FET