Building a dual VCO module

[whomper]

I am thinking about creating a dual VCO module and would like to use a single TUNE knob (dual gang) for both modules.

Is the dual gang reliable enough so that once I adjust the trimmers to be in tune I will be able to use a single pot to tune both modules?

I am reckoning to still require a FINE pot, not sure whether a 1K or 10K though.

[neandrewthal]

I don`t see why you need a dual gang pot. Why not just send the output of the pot to both PCBs?

[whomper]

I am under the impression that it would be advisable to separate the two circuits, and each pot to be connected to each circuit.

Can I safely connect a single non dual gang pot to the two boards? I am looking for all other pot-requiring features to be administered using a single pot.

[Tim Servo]

Hi Erez,

What you want to do is simply take the voltage from a Master Tune pot and run it to a CV input on each VCO, like Neandrewthal suggested. Because of the summing resistors (the 100k resistors on the CV inputs) the two VCOs will still be well isolated from each other. You can try something besides 100k for the summing resistor to change the range of the Master Tune pot (higher value will reduce the range). Running a single CV to several VCOs is very common - this is what is done with the keyboard CV, for example.

Tim (more Cro-Magnonesque) Servo

[neandrewthal]

[whomper]

Looking at this link:
http://www.musicfromouterspace.com/analogsynth/cvdistributor.html

Perhaps one needs to buffer the CV signal before sending to multiple targets.