MM660 panel

All about it

A waveshaper with a real difference!

This module takes a quadrature pair of sine waves (such as the 2-pole and 4-pole outputs of an oscillating 4-pole filter) into its sine and cosine outputs, and encodes the phase angle of the sine input into a 6-bit number that is available on the staircase outputs (both control voltage and audio), and as individual outputs (d0 through d5). This number is graphically represented by 32 LEDs representing the circle that the quadrature pair describes.

The staircase out gives a Poly-61 like digital saw sound, and the individual data outputs can be used as pulse clocks or audio multipliers-with residual errors from lower multiples giving increasing imperfection as they go higher in frequency.

The fun really begins when the input wave shapes and their phase separation are varied, or input waves with different frequencies are used. In this case the phase angle of the saw starts to distort, and the sound becomes more metallic and even takes on a cross-modulation character. The individual data outs become more chaotic and almost merge into digital noise.

To top it off, two CV inputs (one for sine and one for cosine inputs) can level-shift the inputs to cause even more mayhem!

The circuit uses no micro controllers - it is a combination of analogue computing and 74HC high-speed logic that can comfortably handle input signals from LFO speeds to right through the audio range and beyond.

The name is inspired by the Roman philosopher Boethius, and his notion of the wheel of history, which resonates in modern culture as the "wheel of fortune", and was also a favourite concept of Tony Wilson of Factory Records.

Tech Notes

Both audio and control inputs accept very low frequency (DC) voltages-input scaling is the only difference. 

This iteration of the module is almost complete - we are intending to add an offset control to switch in a -5V offset to allow cycling function generators to be centred around zero volts access all four quadrants.

Tech Specs

Power requirements

+15V: TBC

-15V: TBC

+5V: TBC

+12V: Not required

+24V: Not required


Buchla-compatible  (4U, quarter-panel) single unit

38mm depth below mounting rails with connected power cable 


User manual on its way!



In late prototyping; expected production northern autumn 2019.


Watch this space