Tone control circuit is used to adjust the tones before entering the amplifier. Tone control over equipped with a loudness and filter directly without using the switch to disconnected or connected. Part of his filter that is C1 and R1 from ground to input , and for his loudness on the R4 and C3 are connected to the input and then go to VR1. C2 and R3 go from ground to the input . After the input is set by volume or VR1 then procesed again by treebel ie C8 , R13 , R14 , and VR2 . Bass on R10 , R11, R12 , C7 ,C8 , and VR3. For supply voltages has been given a stabilization in Q3. See schematic below : Click to view larger Part list : R1 = 100K R2 = 50K trim R3 = 22K R4 = 15K R5 = 1K R6 = 4K7 R7 = 330K R8 = 330K R9 = 3K3 R10= 5K6 R11= 8K2 R12= 5K6 R13= 1K R14= 1K R15= 50K TRIM R16= 50K TRIM R17= 330K R18= 4K7 R19= 47K R20= 1K R21= 4K7 R22= 2K2 R23= 100R R24= 22K C1 = 15n C2 = 15n C3 = 560p C4 = 4u7 C5 = 33u C6 = 4n7 C7 = 39n C8 = 39n C9 = 4u7 C10=4u7 C11=470u C12=100u Q1 = C1815 Q2 = C828