After using the second PCB revision (v0.3.3) and applying some rework, some more fixes are left for a new PCB revision:

• General: Use IDC connectors for board-to-board connections (easier to build the cables)
• Channel Mixer: Use new resistors in the reference value ladder of the microphone level meter (aka VU meter)
• Channel Mixer: Reduce adjustable microphone gain range to 30dB instead of 45dB
• Channel I/O: Reduce mic-preamp to 30 dB (so max. gain is 60dB instead of 80dB)
• Line I/O: Remove adjustable gain on line input and re-calculate LP filter -- or completely remove the second OpAmp
• Line I/O: Reduce summing gain to -6 dB (so output is 0 dBu nominally)
• Channel Mixer: Replace SMD LEDs with 2x5 mm rectangular THD LEDs?