DIY Quantussy

I must have an obsession with Peter Blasser’s Quantussy, the five oscillator cluster in his Cocoquantus. When Josh Rodriquez sent me five Quantussy Petal PC board, there was no doubt I would build it. I’ve written extensively about the Quantussy here on my blog. And in two recent posts I gave a redrawn schematic diagram and showed a test of the first assembled petal. One petal by itself is only an oscillator. The magic happens when five of these are interconnected (see the interconnection diagram of the forty wires, in the previous post).

Construction

The assembly is mounted between two one-foot square sheets of clear plexiglass that I had made at a local glass shop. PC boards are suspended below the top on one-inch nylon standoffs. Below, half-inch standoffs extend to the bottom side, giving plenty of support for plugging the banana jacks. The first challenge was to lay out the petals in an approximation of a pentagon. I worked up a drilling template.

LEDs in the center are soldered to the boards, and glow through the case. I added two features to my DIY version. Each petal got an LED that blinks at the rate of oscillator. These LEDs are orange in color and mounted on a CGS LED driver PC board (glad I stocked up on these years ago). The other feature is a secondary Castle output. This comes from the op amp buffering the CV from another petal that internally controls the rate. The other panel bits include a three-position toggle switch for Low, High, and Medium range.

Banana jacks:

Green – Input for triggering the mode changes indicated by LEDs
Blue – CV input for rate
Yellow – secondary Castle output
Red – primary Castle output
Orange – triangle wave output

Wiring proceeded in two phases. The first was connecting the jacks, switches, and LED boards to their respective petal boards and then running the power wiring. (Power is supplied by a single LM7809 regulator.)