A-149-3 Fluctuating Random Voltages

The A-149-3 module delves into the classic territory of Buchla’s “Source of Uncertainty,” specifically taking inspiration from the “Fluctuating Random Voltages” section. It provides a suite of interconnected random tools: three distinct noise flavours: a bright noise aka “Blue”, a darker Red/Brown noise source (“reciprocal white noise” for the Allan Strange nerds out there), and finally Pink noise. There’s also a noisy triangle LFO with adjustable rate and randomness, a sample & hold (S&H) with controllable clocking and smoothing, and a vactrol-based slew limiter.

Doepfer hasn’t just replicated the past; they’ve significantly expanded upon it, offering far greater control and breaking out the internal components for independent use. While its sections are internally connected to generate complex, evolving signals reminiscent of its heritage, each core section—Noise, Noisy Triangle, S&H, and Slew—has its own outputs. This means you can use them together for intricate random patches or break them out individually as random utility functions when needed.

The A-149-3 is a great toolkit for generating everything from gentle drifts to complex, structured randomness – a controllable source of West Coast uncertainty. It functions both as a complex whole or as separate random sources for diverse modulation duties — a versatile module for anything chaos.

Features:

• Inspired by Buchla’s Source of Uncertainty 265/266, esp. the “Fluctuating Random Voltages” section.
• Three distinct filtered digital noise outputs: +3dB (a bright noise, aka Blue), -3dB (a darker Red/Brown noise), and Flat (Pink noise)
• Internal Triangle LFO with adjustable Frequency and Range switch
• Adjustable “Noisiness” control to blend Triangle with selected noise (-3dB or Flat via jumper)
• Dedicated “Noisy Triangle” output (N Tri)
• Sample & Hold (S&H) unit with Clock In, Signal In (normalized from N Tri), and Output
• Internal S&H Clock Oscillator (Rectangle Wave) with LED indicator
• Manual or Automatic S&H Clock Period control (Auto mode linked to Slew via vactrol)
• S&H “Correlation” control for output smoothing (feedback)
• Vactrol-based Slew Limiter (SL) with Signal In (normalized from S&H), CV In, and Output
• Manual Slew Time control and CV Attenuator
• LED indicators for Noisy Triangle, S&H Output, Slew Output, S&H Clock, and Slew Vactrol brightness
• Normalled internal connections allow independent use of Noise, N Tri, S&H, and Slew sections