The build is great for beginners learning how to surface mount solder. All the passives are 0603 and there is only 1 IC with a pretty wide pitch.
To adjust the trim pots, input a saw wave. Measure the voltage of the signal going in to a channel and adjust the corresponding channel’s trim pot so the output has the same voltage.
Don’t pay attention to the XWSX, this is the expander for later.
DIY and docs: Github
Organise your case: ModularGrid