Simple Audio Mixer Circuit Based 1 FET

This simple circuit can mix two or more channels into one channel very well and with low noise. For example from stereo to mono.

The circuit can be added with as many channels as possible according to your needs. But in the example circuit here it only has 2 channel inputs. If you want to add more channels, simply add components like R1, C1, and R3 and duplicate them.

Circuit Diagram

Circuit diagram of audio mixer based 1 FET


  • R1, R3 10K Pot
  • R2, R4 100K 1/4 W Resistor
  • R5 6.8K 1/4 W Resistor
  • C1, C2, C3 0.1uF Capacitor
  • Q1 2N3819 Junction FET
  • MISC Wire, Shielded (Metal) Case, Phono Or Other Plug For Output


  • If you want to add a lot of inputs, it is recommended no more than 25 inputs because the gain of the J-FET will be very small.
  • It is recommended to use a protective casing to reduce the insulation that causes hum.
  • The power source for this mixer circuit must be properly regulated, such as using a LM7809, or preferably using a battery.