Hello, I'm just building my first K2. I have no sidetone. When the sidetone level is on 255 I can hear a very weak tone. Also I can change the pitch of the sidetone. I taped with my fingers on the short jumpers R18, R19 on control board and can hear the typical af amplifier noise. So the audio path seems to be OK. Any ideas? Regards Frank DH8JF