1221 OSCILLATOR EXPANDER

this is designed to work with the 1222 Performance Oscillators via the Link port. But it can also work for any other oscillators! (including the incoming kosmo synth voice).

It connects via the rear to up to 3 1222 VCO’s via link cables. It can also connect to oscillators from the output on the front of the module too, to add functionality to any oscillator.

It is basically full of things i was hoping to have in my modular synth voice i didn’t have. This includes a voltage controlled LFO (useful for plugging into a mod wheel as the CV input controls the depth of the modulation) it has square and triangle LFO waveforms and a voltage controller Slide function (portamento with CV over the portamento level. It also has a collective PulseWidth input to be able to control the PWM of the oscillators at the same time but with varying levels, also a collective modulation input and 1v/octave input.

The trim pot is to fine tune the 1v/oct response, so when you have finished building it, plug an octave into the cv input and tune that to make it in tune again.

SCHEMATIC COMING WITHIN THE NEXT 24 hours i need to annotate it.

NOTES :-

-The LED’s are designed primarily for bipolar LED’s because the LFO and voltage can go +ve and -ve voltages. so getting bipolar LED’s is a nice addition, however if you like it to be constant with the other LED’s you use, just use the normal LED’s, it’ll work just as well you just wont get shown the negative voltages, which is no biggy! as usually controlling 1v/oct is +ve voltages, and the LFO swings between +ve and -ve so for most purposes it’ll be the same, so its your call!.

-Keep the rear ribbon cables from the expansion module to the 1222 oscillators nice and short (i have no evidence of long ones effecting it any differently but my mind is saying to write this haha), and also make sure that you have all of the modules on the same power! I had a problem with one of the first prototypes of this module where the voltage was coming out a bit noisy to the oscillators, i tried everything to solve it, it turned out my power supply was to blame as i had too much plugged in, i found that this setup can amplify any power supply issues, once i reduced the load on the power supply the problem vanished. Im not saying this will be a problem for you! (i did have a lot plugged in!) but if you notice there is a raspyness to the oscillator output now you have the oscillators plugged in, first thing to look at is the power supply!