I have built the LMNC simple VCO with PWM and added 1V/oct, CV pot, sync, fm, and the Track, Centre and High track trimmers using the 1222 Performance oscillator schematic. It all works and it tracks 1V/oct over the whole keyboard. I found it difficult getting the course tune spot on so i’ve added the fine tune pot and now it won’t track 1V/oct. Not even close. It has messed up the scaling completely.
Can anyone explain why and what i can do to get it to track now?
Would i need to add the reference point so i could get the volts trimmed up and if so how can i do this without adding the rotary switch as i want to keep the variable course tune pot.
Thank you and live long and prosper.