Control PW of 3 VCOs using one pot

involver · Joined: Dec 19, 2011 Posts: 5 Location: London

I am planning the front panel for my new synth. Due to space considerations I have decided to have one control for the pulse width of all three VCOs. (I will also have inputs for each VCO's PWM so I can control them separately with CVs).

I am using curetronic System 100m VCO's. There is an input for the PW pot on each board and also a PWM CV input. Full schematic is here:
http://www.curetronic.com/curetrbau/neubau/112m.htm

What is the best way to do this? Triple gang pots seem a bit difficult to find?

JovianPyx · Posted: Fri Feb 17, 2012 8:13 am Post subject:

Since each VCO will have it's own PWM CV input, you can add a summing amp to each PWM CV input so that each VCO actually has 2 PWM inputs. One PWM CV input from each VCO just gets a CV jack, the other receives a voltage fed to it by a single pot. Since by it's nature a summing amp inverts, each summing amp will have to be followed by an inverting unity gain amp. So two opamps are required for each input.

I wish that the schematic were labeled, since it is not is difficult to make a more in depth analysis.

HTH

3vcos · Joined: Oct 26, 2006 Posts: 106 Location: California

No one controls me !!!!!!! Laughing

involver · Joined: Dec 19, 2011 Posts: 5 Location: London

Not even by CV or FM? Laughing