ARC - Noise Rainbow


ARC's Noise Rainbow is comprised of an analog noise generator with a number of timbres and a digital pseudo-random noise generator. Latter can produce a variety of signals, depending on the external clock rate, from low-frequency random pulses to digital white noise.



Both noise sources of the module are based on new old stock Soviet integrated circuits KГ401 and К176ИР10.

Analog noise:
The white noise has equal energy over the entire frequency range. Grey noise has been notch-filtered and shows a notch in the frequency band at around 1kHz.
Colored noise is too filtered white noise but the timbre is set with the Colour potentiometer. The fully counterclockwise position equals red nosie (low pass filtered, damped high frequencies), the center position equals a blue noise (high pass filtered i.e. more present in the treble and damped in the low frequencies), the fully clockwise position will generate a violet noise (high pass filtered as well but with a drastic slope and without any low frequencies.)

Digital noise/random:
The section emits a constant stream of pseudo random pulses at the RND output. The frequency of the internal linear oscillator can be set manually or be modulated via VC Rate, turning the potentiometer into an attenuator as soon as a cable has been patched. Alternatively you can inject an external clock e.g. a tonal square wave VCO for "pitched noise" applications.


noise: outputs for grey, white and coloured noise
random: digital random output, clock input, Rate CV input


3U Eurorack module, 3HP wide, 38 mm deep
current draw: 20mA at +12V and 10mA at -12V

0.049 kg
Article Number

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