Hi Mikhail,

> I wonder can this boards used to build the polyphonic synth
> Sorry, if it sounds stupid, I'm really new to all this stuff.

Not a stupid question at all.
Basically yes, but it would be always like the Oberheim SEM based
two/four/eight/voice synths, with individual controls for each voice.
Also an important part is missing: you still need a keyboard or a
midi-interface, that provides polyphonic CV/Gate.

Florian