6 Channel Mixer with bass treble and echo controls

This is by far the most complex project that I have posted on my blog. I always wanted to build my own audio mixer but due to limited time I was not able to build anything like this.


I wanted to make the circuit as simple as possible but since I also wanted to add bass, treble and echo effect controls, the circuit is not that simple. It is not for those beginner that has not yet build any kinds of electronic circuits. I also have not yet designed a PCB for this. You can add more channel as many as you want.

The echo circuit is made from PT2399 IC echo IC. This is simple echo solution that I know. The circuit can be powered by 12V power supply. The CD player/Aux input have no tone contol and preamp circuit. You may want to add it by just copying the tone control of the mic channels. I decided not to add this to make the circuit simple.  Balance or pan controls is also omitted to make it simple.

Tone Control Frequency Response simulation:

I have only simulated the tone control circuit using simetrix. Other part of the circuit is not yet simulated or tested.


  • The circuit is not yet tested since I have no time building it.
  • The Photo of a mixer is not the actual mixer(I have not yet build this circuit)
  • IC2 is PT2399



  • IC2 pin1 should be connected to +5v supply
  • C49 value should be 0.001uF
  • Volume controls value can be 50-100k
  • C52 should be connected to pin15 of IC2 instead of R97
  • C50, C51, and C52 value should be 4.7uf
  • C58, C4, C12, and C17 value should be 2.2uf