Motivation
It is mostly sufficient to mix only two or three audio or control voltages together to enhance your sound or the sound animation. So this small mixer comes in handy for mixing CV sources and audio sources as well. This version is DC coupled, so you can use it for AC and DC mixing. There is an inverted output added. You can reverse the DC-CV mix with it or experiment with feedback loops in the audio domain.
Specs and features
- Three inputs
- Inverted and non- inverted output
- Runs on +/-12V and +/-15V
- Power consumption below 20mA each rail
Implementation
Schematic
Small mixer schematic: Control board
Small mixer schematic: Main board board
Description:
Control board: Straight forward design. The mixer is completely DC coupled. So you can use it for CV mixing as well as audio mixing. IC1B, C, D buffers the input signal. With this buffer and the 1Meg resistors at the input the input resistance is held constant.
Main board: IC1D sums the three inputs and inverts the signal. IC1B corrects the phase. IC1C and IC1A are the output buffers.
Calibration
- None
Building hints
- None
Special parts
- None
Download
Small mixer control board documentation downloadSmall mixer control board Gerber files download
Small mixer main board documentation download
Small mixer main board Gerber files download
Small mixer *.fpd file download
Small mixer: Front view
Small mixer: Populated control PCB
Small mixer: Populated main PCB
Small mixer: Side view
