The CGS502 provides a simple means to turn any control voltage in to voltage steps corresponding to well tuned (equal-tempered) tones of musical scale. It is scaled to 1V/Octave so a 0V to +5V envelope at one of the inputs produces a staircase of voltages corresponding to a chromatic scale.

If patched to the 1V/Octave input of an oscillator tuned to 'E', a slope of 1V applied to the input will produce the following steps of musical scale:

E-F-F#-G-G#-A-A#-B-C-C#-D-D#-E.
(Normal chromatic scale)

If [1/6 Select] is enabled, then the scale produced will be:


E-F#-G#-A#-C-D-E
(whole tone scale)


If [1/3 Select] is enabled, then the scale produced will be:


E-G#-C-E
(scale of major third steps)


If both [1/6 Select] and [1/3 Select] are enabled, then the scale produced will be:


E-F-G#-A-C-C#-E
(Alternating half-step/minor third step)


Since the Scale Select inputs can be activated very quickly, the CGS502 can produce a wide variety of tonal effetcs, quickly moving between four different types of musical scales (chromatic, whole-tone, augmented triad, and a six-step major-minor scale often heard in certain oriental music).

Accuracy of the CGS502 is 3-cents maximum deviation from the ideal equal-tempered semitone over a 5-octave range while the response time for all channels is about 8 milliseconds.

PCB info: 3" x 6" with four 3.2mm mounting holes 0.15" in from the edges