Eurorack Module

Noise VCA

Noise Generator with state-variable VCF and VCA

An all-in-one noise ‚voice‘. A white noise generator followed by a state-variable VCF (switchable between band-, high-, or lowpass characteristic) with adjustable resonance (Q) and a VCA makes this module ideal for most standard noise applications. The integrated filter provides a wide range of rich and colourful noise sounds. The VCF has a 2nd input, allowing one to combine external audio with noise, or to replace the VCF’s noise input completely with an external source.
Further, there is a sub audio output providing a random CV for modulations.
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 ‚Offset‘ knob allows one to shift the VCA’s start point by adding a negative or positive voltage to the VCA’s CV input.
From Revision 2, the control elements on the panel have a slightly different arrangement. Further, the polarizing VCF-CV level knob ‚VCF CVin‘ has been replaced by a knob-switch combination, allowing more sensitive control of the CV input level – due to the  CG products module’s  standard arrangement.

Noise VCA

• 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

• Optionally with banana sockets (on request)
  

• Width: 10 HP

• Dimensions: 128,5mm x 50,5mm

• Depth: ≈40mm

• Supply voltage: ±12V

• Power consumption: ≈42mA (positive rail)
  

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

Documentation

PDF Download

Panel drawing

Side view right

Side view left

Banana Version

1. Noise VCA with P+H control

In this standard patch 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

2. Noise VCA with external Signal

In this example 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

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

4. VCF and VCA working independently

When using the VCA with white noise (or Sub F) as signal source, the VCF can be used completely independent to process 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

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.