Modular 55 Series Circuit Design, Generates White and Pink Noise, Two White Noise Outputs, Two Pink Noise Outputs, 4 HP, Includes Ribbon Power Cable and Screws. The Behringer 903A Random Signal Generator is a Eurorack-compatible noise generator module based on the authentic circuit designs from the Moog Modular System 55. The discrete circuitry of the Moog Modular System has a distinctive sound and was used by artists like Keith Emerson Stevie Wonder Tangerine Dream and many other pop rock and jazz musicians.The 903A module features white noise and pink noise circuits each with two outputs. White noise generates all frequencies at the same level while pink noise uses a logarithmic algorithm that follows the way people hear with a stronger perception of low frequencies. Use the noise generators as audio sources or as a random CV/gate source to drive sequencers VC LFOs and other time-based module inputs.