4720 VCO

The VCOs, like most of the modules, needed some love. Here two of them are removed from the case.

I attempted to trim the waveforms to approximate the ideal shapes by using the trimmers mounted on the PCB. The oscilloscope pictures show about the best results I could get for the triangle and sine outputs. As you can see there are "spikes" at the bottom of the triangle wave that also is visible on the sine wave since that is derived from the triangle. The cause of this is the non-ideal (non-zero) reset time of the sawtooth waveform since the triangle is created from the sawtooth by "folding" it over itself.

I will have to decide later if I will try to improve this behaviour. Perhaps it is a part of the design and contributes to the PAiA sound, and in that case I probably leave it as it is.