VCO coarse control

micromusic · Joined: May 05, 2014 Posts: 61 Location: england

All my VCOs track and sound perfect the only small annoyance is that the coarse tune range is over the full frequency in about half of the pot travel , by over half way I am talking to Bats this is the same for all 3 I have made
The fine tune is ok by the way
All components are to the recommended and are hand matched transistors
Is there a simple mod to smooth out the pot range so it works for say 10 octaves
rather than the 40 I get

Thanks

blue hell · Posted: Wed Aug 22, 2018 12:13 pm Post subject:

Without seeing a schematic I'll have to guess .. but could put a resistor (about the same value as the pot resistance) at one of the ends of the pot (positive side) .. or likely could change the value of the summing resistor (make it larger, maybe twice as large) coming from middle of the pot into the input summing opamp.