I soldered all the parts. The layout of the board is terrible but it works.

Some notes: 

• LCD connector is soldered upside down due one-sided PCB. The final version will be soldered on another side of the PCB.

• Trimmers are placed randomly. Not easy to find which does what. Too many trimmers and jumpers. I plan to simplify the input filters and reduce the number of these jump&trim.

• Optional (and different) connectors for audio input (e.g. 3.5mm socket) and power (e.g. small screw terminal block) would be convenient.

• Bad footprint of power connector.

• USB->serial chip on board (e.g. PL2303) would help with the external connection

So, looks like a list of several small improvements for the next version of the PCB :)