Frap Tools Sapel

Tamed Random Source

sapèl / saˈpɛːl / s.m. [dialect from the northern area of Modena – Italy, uncertain etymology: probably from vulgar Latin sappa, ‘hoe’, meaning ‘roughly hoed’] – ‘mess’, ‘muddle’, ‘chaos’.

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 (+3dB/oct spectrum)
white noise (0dB/oct spectrum)
pink noise (-3dB/oct 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 1V/oct scale;
quantized random voltage with n+1 stages tuned in octaves referred to 1V/oct 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.