Simplest DIY / Homemade Moog / ARP / KORG Filter Sound Analog Synthesizer EVER

This is a pulse width modulated oscillator, routed through a light-controlled resonant low pass filter. My objective was to produce a true synth sound with minimum parts count and all commonly available parts. By “true synth sound“ I mean FAT dual oscillator tonality (via PWM) and a sweet high-resonance low pass filter. The light-control aspect gives amazing musical expression, as seen in the video clip. Made from all generic op-amps. (LM358, LM1458, LM741 all work equally well.) It can be tuned to any scale via the eight tunable potentiometers. Through a nice amp it absolutely GROWLS with earth-shaking bass frequencies. Here is the updated schematic: