The audio mixer schematic we propose is developed arround 4 amplifiers build inside SSM2024 produced by Precision Monolithics Inc. (PMI) and is voltage controlled (VR).
The maximum VR voltage is 5.5Volt. The signal/noise ratio is 90dB and 130Khz band wide. This 4 channels mixer works great at +- 15Volt but you can use voltages between 9Volt and 18Volt.
4 channels mixer voltage controlled
Audio mixer circuit schematic