How's the Serenity?

A set of four reverse sigmoid chaos circuits running at different frequencies, with pots to feed each section into another and influence, sync, sort of, the action. Each section has a CV input affecting its reset or crossover timing: for the faster ones the results are obvious; for the slower ones, give it a few hours. The reverse sigmoid circuits are similar in concept to the Mackey-Glass based design of the NLC Frisson, but greatly simplified to a bare minimum of parts: an integrator, two all-pass filters and a nonlinear stage with two feedback paths. Any capacitors work, so long as all three of a section are the same: these use 1 uF, 10 uF, 2x 1000 uF in series and 2x 2200 uF in series, the 2200 uF ones through the panel. They work quite differently to the Sloth chaos circuits, with a number of ripples or rolls between each attractor, and each section's three outputs track each other, the faster ones delayed by a few seconds, the slower ones by minutes. Four circuits influencing each other make longer tracks with many different but related musical events, and weird delayed CV effects: a band whose members all do their own thing but every now and then connect and achieve structure, which slowly scatters and reforms in new ways. There are also two difference rectifier circuits, outputting complex mixes of the individual chaos circuits.

Key features

• Four chaos sections, each with a CV input and its pot, and three outputs A, B and C that track each other
• Four SYNC pots feeding each section into the next: 1-2, 2-3, 3-4 and 4-1
• Four more outputs on the right, marked − and + on the photographed panel, from the two difference rectifier circuits
• A bipolar LED on each of the 16 outputs; six 2200 uF capacitors through the panel
• 24 HP; Nonlinearcircuits publishes no current draw, depth or assembled price (it sells the DIY PCB and panel), and ModularGrid lists none