Last week I finished up the construction of the 3 VCO Opto module to be used with the opto sequencer. The design is very simple. Once again I utilize 555 IC chips as my oscillators. The module has 2 mono outputs which can he perceived as a stereo signal or mixed individually. Each set of knobs controls the frequency and duty of separate 555s. Opto-resistors are wired in parallel to each pot giving a wide tonal range. The big chicken head controls a multipole switch patching modulation input of 555s to various circuit points. Each of the output VCOs can be synced to that if desired. The 3rd VCO is only for patching and acting as an LFO. Everything is wired on the small perfboard with solidcore copper wire.
Here are the videos of the synth in action. Please be warned that some sharp tones may occur once in a while.
Additional photos can be seen in the gallery.