The SAPÈL is a random control voltages source for Eurorack modular systems. It is composed of two main sections, one that generates audio noises, in 4 different versions, and another which includes two specular random clock, random voltages, and clock sources.

Noise outputs are color coded, based on the noise colors, and include:

blue (+3 dB / oct spectrum)

/ spectrum) white noise (0 dB / oct spectrum)

/ spectrum) pink noise (-3 dB / oct spectrum)

/ spectrum) red noise, a.k.a. brown or brownian (-6dB/ oct spectrum).

The random voltage and clock section features four uncorrelated random CV generation paths, divided in;

fluctuating random voltage;

quantized random voltage with 2n stages tuned in semitones referred to 1 V / oct scale;

/ scale; quantized random voltage with n+1 stages tuned in octaves referred to 1 V / oct scale;

/ scale; non-quantized sample & hold.

It is also possible to set a probability distribution with a potentiometer, and apply (or do not apply) the chosen distribution setting to each of the four paths independently.

Furthermore, each of the two random sources section features an independent built-in clock generator, with clock output and random clock output, which can be used in “more than” or “less than” mode. It is possible to use an external clock signal as a clock source, bypassing the built-in one. In addition to that, it is also possible to hand trigger the clock via a manual sample & hold button, which can be also modulated by gate signals.