Mixer II
Ultra simple two-channel mixer in 2hp. You can mix audio signals, such as control voltage, like envelopes. There are attenuators and mute switches per channel.
I built the first iteration of this module for my techno rack. I needed a slim mixer to sum the two channels of my hihats module because I didn’t have more channels left on my main mixer 💡
In the second run (revision 2), I then needed the requirement to be able to sum control voltage as well. I wanted a way to mix envelopes for side chaining and have them non-inverted.
At some point it bothered me more and more that it clicked so much in the sound when muting with the switches. That’s why I removed them completely with revision 3. Mute is still possible with the volume pots. I also missed the variable master gain, with which I could still adjust the output, especially when mixing envelopes from other modules. That’s why I added it as a trimpot to be more flexible.
Features
- ✅ 2 channels
- ✅ Attenuation per channel
- ✅ Mixes audio signals and control voltage
- ✅ Variable master gain
- ✅ Buffered inputs
Specifications
Right and left view on the module:
Control board (bottom):
Main board (top and bottom):
Resources
Revision 1 (stripboard prototype)
Revision 2 (breadboard prototype)
What’s new? Implemented a non-inverted output.
Revision 3 (breadboard prototype)
What’s new? Removed switches (and thereby their clicking) and added variable master gain.
- Video Demo: Mixing Hihats
- Video Demo: Mixing Envelopes
- Schematic (PDF)
- Showcase and feedback on Reddit, Modwiggler and Instagram
- Improvement potential on GitHub (issues)
Revision 4 (PCB prototype)
What’s new? Brought it on PCB level.
- Video Demo: Mixing Envelopes
- Video Demo: Mixing Hihats
- Video Demo: Mixing Bass Line And Hihat
- Schematic (PDF)
- BOM (XLS)
- Panel Gerber files (ZIP)
- Main board Gerber files (ZIP)
- Control board Gerber files (ZIP)
- Showcase and feedback on Instagram and Reddit
- Improvement potential on GitHub (issues)