I designed this VCO to be inexpensive but reliable, like a sack lunch. The schematic is based around the AS3340 datasheet, along with a number of modifications to make it usable in a Eurorack system.

Features

• 3 waveform outputs (triangle, square, saw) 10vpp
• Stable tuning, as is typical of the AS3340. Once you initially tune the circuit, you likely won't need to fiddle with the trimmers in the back ever again
• 2 forms of circuit protection: schottky diodes on the power rails, which will prevent damage in the case of polarity reversal, and a shrowded box header on the power pins. Apparently a lot of companies do not use these box headers, which is confusing since they are super cheap and they have the benefit of physically preventing you from pluggin power in backward. Seems like a no-brainer.
• Hard Sync input
• PWM for square wave, with a range from 50% to 0% (at the far clockwise on the knob, 0%, the waveform becomes silent)
• PWM CV input - when CV is patched in, the PWM knob becomes an attenuator for the CV
• Linear FM input with attenuator knob
• Fine and coarse frequency knobs
• LED status light (this is optional and it's only purpose is to add some extra color to your rack)
• A little owl, hanging out
• A topographical map of Mount Rainier in the background, if you ever find yourself lost out there with only your trusty VCO to guide you

Your purchase includes:

• the Sack Lunch VCO
• both black AND white front panels
• knob color of your choice (white, black, red, yellow, blue)
• LED color of you choice (Blue, green, yellow, orange, pink)
• Power cable
• M3 rack screws