CG Products
design — construction — sound

Eurorack Module

Noise VCA

Noise Generator with state-variable VCF and VCA

Noise VCA frontal view
Noise VCA frontal view
  • Noise generator with integrated VCF and VCA
  • 3 direct Outputs:
    • White Noise
    • Sub F (Random CV)
    • VCF Out (Coloured)
  • Switchable VCF characteristic:
    • Highpass (12db)
    • Bandpass (6db)
    • Lowpass (12db)
  • Adjustable filter resonance (Q)
  • Switchable 2nd VCF signal input:
    • White noise only
    • White noise & external signal combined
    • external signal only
  • VCA with switchable CV mode:
    • linear CV
    • 0 (mute)
    • exponential CV
  • Width: 10 HP
  • Dimensions: 128,5mm x 50,5mm
  • Depth: ≈40mm
  • Supply voltage: ±12V
  • Power consumption: ≈42mA (positive rail)
  • Optionally in banana version
An complete all-in-one noise ‘voice’. The combination of a white noise generator with state-variable VCF and VCA features advanced sound processing in one module and reduces the need for extra modules and cables.

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The integrated filter (with selectable high-, band-, or lowpass characteristic) allows the creation of rich and colourful noise sounds. It has a 2nd input for combining the noise signal with external audio, or for replacing the VCF’s white noise input completely by an external source. Resonance of the filter can be adjusted up to self-resonance; in this mode, the filter may be used as a voltage controlled oscillator. By using a short impulse signal as input, the slightly resonating filter can be triggered (‘pinging’).
Despite of the white noise and the VCF direct outs, there is a 3rd low frequency output called ‘Sub F’, providing a random CV for modulations.
The VCA has an input selector switch for determining the input source, whether White noise, Sub F or VCF.
The VCA’s CV mode can be switched between exponential and linear characteristic, with a muting option when the switch is in its middle position; the knob ‘Offset’ is allowing to shift the VCA’s starting point by adding a negative or positive voltage to the VCA’s CV input.

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  • Noise VCA drawing

    Drawing

  • NoiseVCA side view right I

    Right side view 1

  • NoiseVCA side view right II

    Right side view 2

  • NoiseVCA side view right III

    Right side view 3

  • NoiseVCA side view left I

    Left side view 1

  • NoiseVCA side view left II

    Left side view 2

  • NoiseVCA banana version

    Banana version

Soundfiles

White Noise; VCF out with LFO cutoff frequency modulation and varying settings of Q.
a) White; b) VCF Lowpass; c) VCF Bandpass; d) VCF Highpass

Noise VCA (VCF LFO-modulated) followed by Delay1022 .
Delay1022 and VCA controlled by Peak&Hold (Input: Drum Machine)

Noise VCA (White Noise VCA Out) followed by Delay1022 (filtered with Noise VCA VCF).
Delay1022
and Noise VCA controlled by LFO and/or Peak&Hold (Input: Drum Machine)

Noise VCA with VCF ext. In: XR22VCO FT; VCA Out (White Noise) followed by Delay1022.
Modulations: Peak&Hold (Input: Drum Machine) with Add1

Or listen on

https://soundcloud.com/cg-products/sets/noise-vca


Audio routing

NoiseVCA svg Block Diagram

Examples

Simple patches with other (CG Products’) modules

NoiseVCA controlled by Peak+Hold

1. Noise VCA controlled by Peak+Hold

The Peak&Hold‘s ‘Release’ output controls the VCA with a dynamic envelope shape, while the Peak&Hold‘s ‘P+H’ output is modulating the VCF’s cutoff frequency.

PEAK+HOLD Input: Drum Machine

NoiseVCA with external signal

2. Noise VCA with external Signal

The XR22 VCO FT‘s squarewave output is applied to ‘ext VCF In’; the Peak&Hold is modulating the Noise VCA’s VCF cutoff frequency and the VCA.

 

PEAK+HOLD Input: Drum Machine

NoiseVCA - impulse triggered VCF

3. VCF triggered by impulse signal

Short impulse signals can be used to trigger the VCF, generating ‘ping’ like sounds. Here the Peak&Hold‘s impulse output is used to trigger the VCF; its ‘P+H’ output is modulating the filter’s cutoff frequency.

PEAK+HOLD Input: Drum Machine

NoiseVCA - VCF and VCA independently working

4. VCF and VCA working independently

When using the internal VCA with white noise (or Sub F) as signal source, the VCF can be used complete independently with another signal; or the VCA can generate dynamic accents to the 1st (VCF) audio output – by shifting the VCA’s offset level. Here the VCF’s audio input is the impulse-triggered Delay 1022.

PEAK+HOLD Input: Drum Machine

NoiseVCA - SubF modulated

5. Sub F modulating CVs

The ‘Sub F’ output can be used to modulate the VCF cutoff frequency and/or the VCA – random sounds such as ‘thunder’ or ‘crackling’ can be generated.