Simple and cheap mixer circuit. This circuit supplied using 9V power supply. There is high/low-sensitivity switchable inputs for each input channel.

3 Channels Mini Mixer Circuit diagram :

Part List :

P1,P2,P3_________5K Linear Potentiometers

R1,R11,R15_____180K 1/4W Resistors
R2,R12,R16_______2M2 1/4W Resistors
R3,R13,R17_____750R 1/4W Resistors (See Notes)
R4,R14,R18_______1K 1/4W Resistors
R5______________15K 1/4W Resistor
R6_____________220R 1/4W Resistor
R7_______________1K5 1/4W Resistor
R8_____________820R 1/4W Resistor
R9_____________150R 1/4W Resistor
R10____________100K 1/4W Resistor

C1,C6,C8_________1µF 63V Polyester or Electrolytic Capacitors
C2,C4,C7,C9____100µF 25V Electrolytic Capacitors
C3,C5__________220µF 25V Electrolytic Capacitors

Q1,Q4,Q5______BC550C 45V 100mA Low noise High gain NPN Transistors
Q2____________BC547 45V 100mA General purpose NPN Transistor
Q3____________BC557 45V 100mA General purpose PNP Transistor

J1,J2,J3________3mm or 6mm Mono Jack sockets

SW1,2,3,4______SPST Toggle or Slider Switches

B1_______________9V PP3 Battery

Clip for PP3 Battery

A mini roulette circuit, as soon as the switch S1 the output next to pin 1 of the IC1a the voltage is “sharp”,The oscillator circuit output IC2b, IC2c work out.alarm clock pulse generator fed to IC3, a voltage “high” output to the output pins 3, 11, and pin 12 of the IC3, the LED1-LED10 light track sequence. Section LED11 parade high - low instant. The output of pin 3, 2, 4, 7, 10, of IC3 represented by high points,Output pins 1, 5, 6, 9, 11 as a replacement for of the IC3 with the low points.The roll-over prize meant for the LED12.The IC1b, IC2a and IC2d like controls.

Resistor R2 and capacitor C1 determine the punctuation mark of the output “excessive” output from pin 1 of the IC1a. The capacitor C1 through R2. as you press the switch and the voltage shelve across C1 spirit little by little swell until the greatest level. It will reset the flip fall down IC1a suit the output next to pin 1 is “low”. And the oscillator output circuit to pause working, but at hand are a number of LED illumination are pending, it might exist to facilitate we close up being the LED. So carry out not concern, it desire switch a only some time.since, particular a schedule punctuation mark with the aim of the R2 and C1. The diplomacy are compulsory to keep a 6-volt power supply. If distorted is 9 volts, requisite try representing security reasons.