Stereo 4-In 4-Out Mixer
Stereo 4-In 4-Out Mixer
A Eurorack size audio mixer. Mix up to 4 audio input channels, the output is duplicated 4 ways with level control on each output.
Mixers will usually attenuate the inputs so the combined output doesn't overload and distort. So for a 4 input mixer each input is cut to 25% level. This mixer has a gain control that allows compensation for the attenuation when less than 4 inputs are being used. The gain goes up to 4X, so a single input can make it through the mixer with no attenuation.
Features
- Active mixer with buffered inputs and outputs
- 4 input channels with mix level controls
- 4 output channels with output level controls
- Gain control
- 20-20KHz frequency response
- 5-12V single supply
- Compact size, low power
Using a 5V supply this mixer works with up to 2Vpp audio signals (consumer/pro line audio levels).
Design Documents
| Schematic Diagram | 4x4_mixer_schematic.pdf |
| Gerbers (mother board) | N901A.zip |
| Gerbers (daughter boards) | N901B.zip |
| 3D Print File | 4x4_mixer_panel.stl |
Build Pictures
Mother board
The board is designed for DIP-8 op-amps, but I used SSOP with adapters because... I ordered the wrong ones.
Input Connector Daughter Board
Input Level Control Daughter Board
Output Level Control Daughter Board
Output Connector Daughter Board
Boards Assembled
On Eurorack Panel Skeleton
