The VCDO 58B represents a new breed of sound generation for the modular environment. The primary design goal was to implement a variety of digital synthesis techniques and to combine them together in one module

The most significant wave-shaping feature of the 58B utilizes the technique referred to as Two-Operator FM, providing a wide variety of timbres from mellow bell like tones to complex distortion.

The inclusion of harmonically rich sample based wave tables extends the complexity of the FM effect comparable to multi-operator systems. AM (Amplitude Modulation) is also available on-board as is standard Exponential FM using the Expo FM Jack Conventional analogue VCOs are modulated with externally generated signals from LFOs and secondary VCOs etc. Digital implementation of the VCDO 58B affords superior FM stability with internally generated, phase locked, sine table modulator. The FM Index function controls the amplitude or depth of the modulation while the Ratio control tunes the modulator to a rational frequency value relative to the carrier frequency. Phase locking the modulator with the carrier produces beat-free timbres that retain spectral relationships over the entire frequency range. The 58B includes standard VCO wave forms and adds several sample based wave tables. Pulse width modulation and hard sync are also supported. Switch selectable quantized pitch tracking in semi-tone steps or non-quantized continuous frequency control with fine tune.Firmware by DSP designer Eric Brombaugh.

Features:

• 32-bit NCO – 50 micro-Hertz resolution (no zippering)
• Phase-locked FM/PM gives beat-free modulation
• 32 real-time voltage controlled modulation/carrier ratios
• Fractional modulation/carrier ratios for complex sub-harmonics
• Modulation index range from 0 to 314% for a wide range of continuously varying wave shapes.
• Real-time voltage-controlled modulation index for subtle wave shaping
• 32-bit pseudo-random noise generator – won’t repeat for 119 hours at highest frequency setting; longer at lower frequencies.
• Voltage controlled selection of 16 wave forms
• Quadrature secondary output at 90 degrees out of phase
• Amplitude and Pulse width Modulation AM/PWM
• Switch selectable quantized 1V/Oct input
• Audio and LFO range frequency
• Voltage controlled FM Index and modulation Ratio
• Crystal tuning stability with +/-0.005% pitch tracking accuracy over 18 octaves

Waves:

• Sine
• Triangle
• Saw
• Square w/PWM
• Double Pulse w/PWM
• Random Stepped (with CV controlled variable interpolation)
• 10 sample based wave tables

Specs:

• Frequency Range: 18 Octaves
• High 10Hz-10kHz
• Low .040Hz-40Hz
• Output: +/-2.5V pk-pk @1Kohms
• Input CV 0-5V @100Kohms

Modifications:

• Changed knobs to MOTM-style
• Bruce Duncan-provided power supply connection for off-board +5V

From the Modcan B website:

The CV Recorder 57B provides a radical new approach to generating modulation and voltage control signals. The implications for this module are extensive when placed in a modular synthesizer context.

Concept: Combine the ability to record and playback control voltage signal events from standard modules with the tools to shape, mix, loop and time scale these performances in a simple and repeatable manner. A brief list of possible uses for the 57B:

• Create asymmetric LFO shapes from Joysticks or ribbon controller signals
• Control panning and VCA parameters for automated mixing
• Record long analogue step sequence patterns while changing the step voltages and recording the clock simultaneously for later sync operations
• Combine and chain together random voltage patterns with sequences and LFOs on 4 channels
• Record envelope shapes and loop them while adjusting the loop start and end points.
• Perform granular synthesis type effects on CVs using short loops and sweeping the loop points through the sample under voltage control.
• Record lo-fi audio samples and shift playback frequency in real-time.

Features:

• 20Hz-20kHz Voltage controlled variable sample/playback rate with 1V per octave response
• 4 seconds of quad sampling @20kHz. Greater than 1 hour @20Hz
• Quad in/outs with 15 switch selectable channel recording configurations
• Record and playback simultaneously
• Rehearse mode for pre-recording experiments
• Chain multiple samples by recording with different loop points and sample rates.
• 3 loop modes: Forward, Reverse and Pendulum
• Panel and voltage controlled Loop start and End controls
• 3 Playback modes: One shot, Loop and Hold play
• Gate out provides short pulse at loop start
• Trigger input for triggering samples when not in loop mode
• Status Bi-LED indicates various record and playback states
• Channel LEDs indicate arming of channels for recording.
• 120MHz DSP processor and 4MB of parallel SRAM

Specs:

• Sample rate : 20Hz-20kHz (10 Octaves)
• Recording Inputs: +/-5V Pk-Pk@100Kohms
• Outputs: +/-5V Pk-Pk@1 Kohms
• Other inputs 0-5V @100Kohms
• Current Requirements: 50mA @ -15V, 200mA @ +15V

Modifications:

• Changed knobs to MOTM-style
• Bruce Duncan-provided power supply connection for off-board +5V

Dual Quantizer module

Two discrete circuits, functionally independent and identical. Converts continuous signal to DC step output voltage conforming to typical musical scales. Scale listings. Sample acquisition time better than 2uS (500kHz), resulting in excellent response/ conversion with no audible slew. Zero Droop design.

Dual Mode operation

Mode 1: Functionally equivalent to a Sample and Hold. Voltage step will only change with a rising edge pulse or trigger applied to the CLOCK input jack. Unique design requires no hold capacitor. Result is zero ‘droop’ and infinite hold. Ideal use of mode 1 is in conjunction with a sequencer. The sequencer gate bus can be used to initiate the sampling of each sequencer step.

Mode 2: No-Clock or free mode. Voltage step output changes automatically when the input crosses the conversion threshold determined by the scale selected. This is the mode users will be familiar with when using the MiniWave to quantize. The one difference here is that with each transition a 5ms pulse is output from the PULSE out jack. This provides the ability to trigger envelopes or logic inputs in synch with step changes.

Features

SCALE: Combined 48 scales and chords in 3 banks. Panel and CV control of scale selection. Input 0-5V+ @ 100K ohms.

TRANSPOSE: Transpose scales in 12 semitone increments. Not just an offset function but a true key transposition. Panel and CV control of Transpose. Input 0-5V+ @ 100K ohms

LEDs: Binary numbering indicates scale selected .

PULSE OUT : 5ms pulse or trigger is output whenever a new step is converted. Output +5V @ 330 ohms

INVERT: Logic high patched to jack results in scale inversion. Low voltage input converts to high scale step and vice versa. Excellent for adding variation to a static sequence pattern. Input +5V @ 100K ohms

CLOCK Input : Rising edge pulse initiates sample acquisition. Input +5V @ 100K ohms

INPUT: Signal input to be quantized. Input range +/-5V @ 100K ohms OUTPUT: quantized step output Output range +/-5V @ 330 ohms

Modifications:

Changed knobs to MOTM-style

Differences from quantizing with a Miniwave:

• Outputs a pulse with each change of the output
• Can be clocked like a Sample & Hold
• Quantizes negative input voltages
• Voltage-controlled inversion of output

Listen to this demo:

In the demo each scale in bank B is heard in succession. A new note is generated on each pitch transition by using the Pulse Out to trigger an envelope generator. The input voltage was taken from the the STAIR output of the MOTM-120R. The occasional syncopated rhythm is due to the fact that on some scales, two of the stair steps happen to quantize to the same output value. Thus there is no pulse out and no new note. An irregular jump occurs when the scale changes, simply because the scale change is driven by a very slow LFO and the scale transition usually produces a new note.