My interest in analog synth circuits for music is fairly new. I had a couple classmates in the EET program at WWU who were interested in audio electronics. I played my drums and, never using sound effects/ pedals, I never developed much of an interest in sound synthesis.

I recently joined a new band called Cavale. Ryan (bass) and James (guitar) are both as stellar musicians as they are good guys. They both sport a fully populated pedal board. Every pedal gets used. They notice the most subtle variation in sound (ones I can’t hear). They take effects very seriously. During our first practice Ryan revealed that, with his wife, they construct pedals from kits and paints them. One such pedal was donated to Minus the Bear – which is awesome. But I digress…

This sparked my interest in the circuits involved. I realized that my skills in analog analysis were in need of a definite refreshment, so I spent a few days looking at synth circuits. That’s when I ran across this VCO circuit through Music From Outer Space. It’s beautiful.

Schematic 1

As VCOs for audio synth have a 1v/octave conversion. To do this, the differential pair of U3 is biased out of the linear region. The accompanying waveshaping circuit is also a delightful composition:

Schematic 2

It took me awhile to go through the full circuit. Lacking much analog design experience, there are still some design choices that elude me. However, still inspirational.

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