4-channel mixer with FX sends, drive, line and phones outputs

EDU DIY Output Mixer 2 (mixer for our upcoming EDU DIY Drum system) allows you to build and understand a 4-channel output mixer from scratch. On a breadboard, you’ll set up an inverting summing amp, add a send/return loop, diode distortion, and a headphone driver.
The manual uses clear diagrams and analogies to explain every step, and you can even assemble the kit into a full Eurorack module using the included PCB and panel.

https://www.ericasynths.lv/shop/diy-kits-1/edu-diy-output-2-drums-mixer/