Behringer 903A Random Signal Generator Eurorack Module (8 HP)

Modular synthesists often struggle to introduce organic unpredictability into their patches, relying on static modulation sources that leave performances feeling sterile. The Behringer 903A Random Signal Generator solves this by delivering three distinct noise colours—white, pink, and red/brown—each with dedicated output level control, plus a variable filter for the red/brown output to shape the noise character. Housed in a compact 8 HP Eurorack module, it brings the classic Moog 903A random voltage source into your rack with authentic analog circuitry, enabling everything from percussive bursts to evolving textures.

Who is it for

This module is ideal for Eurorack enthusiasts, experimental musicians, and sound designers who need a reliable source of noise for percussion synthesis, sample and hold, or audio-rate modulation. Whether you are building a generative ambient system or a techno-oriented rack, the 903A provides the raw sonic material to add life and movement to your patches.

Main features

• Three simultaneous noise outputs: white, pink, and red/brown, each with independent level control
• Dedicated filter control for the red/brown output to adjust low-frequency content
• Authentic analog reproduction of the Moog 903A random signal generator circuit
• Compact 8 HP Eurorack format with 3.5 mm TS jack outputs
• Low power consumption: only 10 mA on both +12V and -12V rails
• Mounting screws included for easy installation

Specifications

• Product type: Random signal generator
• Module format: Eurorack
• Module width: 8 HP
• Noise types generated: White noise, pink noise, red/brown noise
• Number of outputs: 3
• Output connectors: 3.5 mm TS jack
• Output level control: Yes, individual for each noise type
• Red/brown noise filter: Yes, dedicated filter control
• Power consumption (+12V): 10 mA
• Power consumption (-12V): 10 mA
• Depth (behind panel): 35 mm
• Inspired by: Moog 903A
• Circuitry: Authentic analog reproduction
• Mounting screws: Included

Tips

Patch the white noise output into a sample and hold module to create random voltages for pitch or filter cutoff. Use the red/brown noise with the filter control to generate thunderous low-end rumbles for cinematic effects. For percussive sounds, mix the noise outputs with an envelope generator and VCA.