EM-802 | Modulation Source Processor

MACHINIST is a comprehensive analog modulation and signal-processing instrument integrating dual wide-range oscillators, discrete noise generation, pulse shaping, voltage comparison, sample-and-hold, and gated exponential slew processing. Operating across the boundary between audio and control voltage, its interconnected architecture transforms elementary waveforms into complex rhythmic structures, evolving modulation, pitched noise, and percussive textures.

Two independent oscillators span an exceptionally broad frequency range of 0.005 Hz to 20 kHz, extending from ultra-slow modulation cycles into the upper audio spectrum. Oscillator I employs a triangle-wave core, while Oscillator II incorporates a phase-locked loop (PLL) architecture with independent square and sawtooth outputs. Dedicated frequency-modulation inputs for both oscillators and hard synchronization for Oscillator II enable complex frequency relationships, harmonic interactions, and evolving modulation patterns.

Three distinct noise sources extend the instrument's sonic vocabulary. Fully discrete white and pink noise generators employ carefully selected transistor networks and capacitive filtering to establish contrasting spectral characteristics, from broadband excitation to warmer, spectrally weighted textures. A third generator utilizes CD4006 shift-register circuitry clocked by Oscillator II, producing voltage-dependent pitched noise, metallic textures, and rhythmically structured sequences. Together, these sources provide a versatile foundation for experimental sound design and analog percussion synthesis.

A continuously variable pulse-shaping circuit converts incoming signals into precisely controlled pulses, ranging from narrow transients to extended gate durations. A dedicated voltage comparator provides additional threshold-dependent processing, enabling trigger extraction, rhythmic restructuring, and logical interactions between internal and external sources. An integrated sample, track-and-hold processor captures incoming voltages under external trigger control or manual initiation, generating stepped modulation, sustained voltage states, and evolving control sequences.

An exponential slew limiter introduces a further dimension of dynamic voltage shaping, combining continuously variable transition times with JFET-controlled gating and selectable rising, falling, or bidirectional response. Beyond conventional portamento, the circuit functions as a percussive contour processor, shaping sharp attacks, controlled decays, and dynamically gated modulation. In conjunction with the discrete noise generators and pulse-shaping circuitry, it enables the construction of tightly articulated hi-hats, metallic transients, and complex rhythmic textures reminiscent of early analog percussion instruments.

More than a collection of independent modulation utilities, MACHINIST is conceived as an interconnected environment for analog signal transformation. Oscillators become clocks, noise becomes pitch, pulses become rhythmic structures, and stepped voltages become fluid gestures. Its architecture encourages continuous interaction between generation and processing, extending from precision control-voltage manipulation to experimental audio synthesis.

01 / OSCILLATORS

Dual independent oscillators spanning 0.005 Hz–20 kHz
Triangle-wave core oscillator with dedicated FM input
PLL-based oscillator with independent square and sawtooth outputs
Dedicated FM and hard synchronization inputs for Oscillator II
Independent LED indication for each oscillator

02 / DISCRETE NOISE SOURCES

Fully discrete transistor-based white-noise generator
Independent pink-noise network with selected transistors and capacitive filtering
CD4006 shift-register-based pitched-noise generator
Variable noise pitch derived from Oscillator II frequency control

03 / PULSE SHAPING & LOGIC

Continuously variable pulse-width and duration shaping
External X input for pulse conversion and trigger processing
Dedicated Y comparator input for voltage-threshold processing
Rhythmic restructuring and logic-based signal transformation
LED indication of pulse-shaper timing

04 / SAMPLE / TRACK & HOLD

Selectable Sample / Track & Hold operation
Dedicated sample and external trigger inputs
Manual sampling via momentary push-button
Stepped modulation, random-voltage processing, and sustained control states

05 / GATED SLEW & PERCUSSIVE CONTOURING

Exponential slew limiter with continuously variable response
JFET-controlled gating via dedicated external gate input
Selectable upward, downward, and bidirectional slew processing
Dedicated slew signal input and output
Percussive envelope shaping, portamento, and dynamic voltage smoothing
Bipolar blue and amber LED indication of positive and negative slew activity

POWER & CONNECTIVITY

±12 V. 10-Pin IDC / Keyed Headers. Red Stripe: −12 V.

LA CIRCUITS, INC.

Official Website — https://circuits.audio
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Email — contact@circuits.audio

https://circuits.audio/