Transistor attenuated tone control circuit

It is an attenuation tone control circuit composed of transistors and RC networks . Lieutenant) 2 is the bass control potentiometer . When the sliding contact is at the upper end of the potentiometer , the island is short-circuited and the bass signal passes easily. The signal is sent to the base of VTz via Q, R, and R7. Due to the splitting effect of C4 and R, the high-frequency components are greatly attenuated and the bass is relatively improved. When the sliding contact is at the lower end of the potentiometer, C is short-circuited, and the audio signal is sent to the base of VTz through Q, R5, C3, and M. Since Q and C are connected in series, due to the small capacity of C3, the bass signal will be affected. The large capacitive impedance makes it difficult for bass to pass through, so the bass is attenuated. So RP2 plays a role in controlling the bass.     The base is a treble control potentiometer. When the sliding contact of the base and the potentiometer is at the upper end of the potentiometer, the audio signal is sent to the base of VT2 through the series connection of bar and c5. Since the capacity of /C5 is very small, the capacitive impedance to the bass is very large, so that the bass cannot pass smoothly, but the treble can pass smoothly. Also, because the impedance of RP3 and C6 is very large after being connected in series, it has little bypass effect on the treble. The treble is relatively improved. When the sliding point of the potentiometer is at the lower end of the potentiometer , the treble is weakened due to the attenuation of RP3 and the bypass of C6, so that the treble is attenuated.