February 7, 2020
By nature all instruments make some sort of noise. Without an oscillation there can be no music, which is why my first eurorack module is a triple oscillator. This design uses transistors in reverse avalanche mode to generate a sawtooth wave. Three separate transistors generate 3 sawtooth waves that are mixed by three 100K ohm resistors. Generation of 3 musical notes allows me to create chords simply by varying the position of the three uppermost knobs. A 4th knob controls tone. The 3.5mm Jack on top is a control voltage (CV) input to adjust the frequency of all three oscillators at once. The jack on the bottom is the output.
The original design is from Look Mum No Computer, thanks! I added the tone control a custom CV circuit. As for the metal panel holding everything together, it’s a remnant of my first Windows XP machine from 2007. It’s cut out with an angle grinder, and sanded to the metallic finish on a Delta belt sander I bought for $30 at a yard sale.