Quantity: 1 in a 1U-wide panel

Ken Stone’s CGS 21 PC Board:

This module is a much expanded version of the Psycho LFO, featuring six free-running oscillators, each variable between LFO and audio ranges, two of which can be switched to have triangular wave outputs. Each oscillator can be switched between low and high ranges, as well as off, and also has a rate LED, to allow visual determination of the frequency at which it is running. As per the original, there are also level and glide controls.

This module can be used to create a range of pseudo-random modulation voltages that can be used to generate unusual sequences, control VCFs or or VCAs etc. When run at higher frequencies, it can be used as a series of audio drones, or to generate complex sounds by frequency modulation a VCO.

Panel:

This is the second module I’ve built using the 8×2 MOTM jack spacing and small pots and knobs. You can download this Front Panel Express Panel.  This format works perfectly for the Psycho LFO, which I had never built because I did not wish to devote 2U of panel space to it, which would be required if standard 1-inch diameter MOTM knobs were used.

Modifications:

There wasn’t room on the panel for Triangle/Square switches for the two oscillators with triangles, and because the triangles impart an undesirable DC offset when switched off, I chose to omit the triangle option and make all six oscillators use square waves. I substituted 2K2 resistors for the specified 1K for the LED current. I could have used 5K6, because the LEDs came from an original Blacet Miniwave. They’re too bright! I’ll probably change them.

Circuit comment:

How many modes of operation does the Super Psycho LFO have?  It has six identical oscillators, each of which can be Off, Low Frequency or High Frequency.  Do the math:  There are 21 different combinations, I think, between one Low Frequency oscillator on to one High Frequency oscillator on.

Here’s the construction. The LEDs are not glued, but are held in place by the wiring harness.

The empty spot on the lower right of the PC board is where the IC for the triangle waves is omitted.  You can  see the two jumpers hard-wiring the square wave option.

Here’s how it looks in the cabinet with the Blacet Miniwave on the left and the CGS Slope Detectors in the same panel format to the right, next to the MOTM-650.