SMS MARS User manual

SYNTHETIC MUSIC SYSTEMS
HAND MADE ANALOGUE SYNTHESIZERS
OPERATORS MANUAL

CONTENTS
INTRODUCTIONS
INTERNAL MODULATION ROUTE
INTERNAL SIGNAL ROUTE
ISOLATION PATCH
VCLFO
VCO
VCF
VCA
ENV
SPECIFICATION
SPECIFICATION
COMING SOON
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INTRODUCTION TO SYNTHETIC MUSIC SYSTEMS
Greetings fellow noise makers. If your reading this you’ve probably just taken delivery of a superb piece of
analogue music making equipment we call the MARS.
SMS is a small friendly company hand building analogue music synthesizers. We’re driven by a passion for
electronic music and the classic analogue sound.
Our objective at SMS is to keep all aspects of our business on a very personal level. We take a great deal
of care and pride in every instrument we build and would like each and every one to lead a long and healthy life,
so if we can help you in anyway please get in touch.
INTRODUCTION TO THE MARS
The MARS ( Modular Analogue Rack Synthesizer) is a highly versatile music synthesizer. As a stand-alone
unit it can create the “classic” sounds associated with analogue synthesizers: silky smooth filter sweeps, squealing
lead lines and deep rumbling basses. Its open ended architecture has been carefully designed for expansion. The
front controls allow the five synthesizer circuits within the MARS ( VCLFO, VCO, VCF, VCA, ENV) to be isolated,
the sockets on the rear panel allow signal and modulation routing to be configured to your specification allowing
for true modular synthesis.
Two optional expansion units, The PLANET7 and The BOB, have been designed to interface with the
MARS. The BOB (Break Out Box) will bring the rear patch sockets to the front of the rack with the addition of a
three colour noise generator. The PLANET7 is designed to sit between two MARS units and will also bring the
rear patch sockets to the front with the addition of a three colour noise generator, ring modulator, sample and hold,
mixer, DC level shifter, lag processor, four attenuator/invertors, multi-jack and two front-to-rear bus lines.
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V
VC CL LF FO OVOLTAGE CONTROLLED LOW FREQUENCY OSCILLATOR
LFO CONTROL
The rate knob controls the speed of the modulation wave form. The LED gives a visual indication of the speed of
the VCLFO.
This output gives a positive sawtooth with an output voltage of +/-5 volts.
This output gives a negative sawtooth with an output voltage of +/-5 volts.
This output gives a square wave output of +/-5 volts
This output gives a triangle wave output of +/-5 volts
The VCLFO is a wide range oscillator used to modulate
control inputs, eg: used for vibrato, tremolo and trill. It is
internally routed to the VCO and VCF (see INTERNAL
SIGNAL ROUTE page 3).
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This gives linear control of the VCLFO rate, eg: from keyboard or envelope.
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VC CO OVOLTAGE CONTROLLED OSCILLATOR
The VCO is the primary sound source within the MARS. It creates the raw waveform which is then processed and
modified by the other synthesizer circuits.
FREQUENCY CONTROL
1. In the ‘-2’ position the tune knob controls the initial frequency of 32Hz by +/- one octave.
2. In the ‘0’ position the tune knob controls the initial frequency of 128Hz by +/- one octave.
3. In the ‘W’ position (WIDE) the tune knob has a range of approximately 12 octaves.
The Modulation knob introduces either triangle, square or no modulation to the oscillators frequency
( a maximum of two octaves, from the VCLFO).
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WAVE SHAPING
The wave knob controls the initial wave shape from the VCO. In the anti-clockwise position a saw tooth is
generated, in the clockwise position a pulse is generated, between the two positions the wave shape alters from
sawtooth through various sawtooth/squarewaves to a 2% pulse. The waveform is fully variable with no fixed point.
The mod knob controls the amount of triangle modulation (from the VCLFO) or envelope modulation routed to the
wave shape. Pulse width modulation can be created using this method.
VCO PATCH POINTS
This is a hard sync input used to reset the VCO waveform using a second oscillator. A wide range of frequencies,
waveshapes and levels will determine the type of sync generated.
This is the main control voltage input for the VCO frequency and has logarithmic characteristics of one volt per
octave, this should be your input from a keyboard/controller.
This is simular to the VCO 1/V input but should be used for external modulation, (eg: LFO, sample and hold,
ENV).
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This is the output for the waveshape generated by the VCO.
This gives external control of the waveshape generated by the VCO.
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VC CF FVOLTAGE CONTROLLED FILTER
The VCF is a low pass 24dB/oct ladder filter, it has the ability to attenuate/eliminate frequencies above the cut-off
point. This type of filter can create sounds associated with classic American analogue synthesizers.
VCF CONTROLS
This signal knob controls the audio signal level coming from the VCO into the VCF. The filter may be over-driven
in the range of 5 - 10.
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The Cut-off knob controls the point at which attenuation begins. Frequencies above the cut-off point are
attenuated at 24dB/oct.
Resonance is used to accentuate frequencies around the cut-off point, as the resonances increase the filter will
begin to ring and will self oscillate at high resonate settings producing a sine wave (the frequency of which is
controlled by the cut-off knob).
The mod knob introduces either triangle, square (from the VCFLO) or no modulation to the VCF’s cut-off point.
The envelope knob alters the cut-off point according to the set up of the envelope generator allowing automated
shaping of the filter negatively and positively.
VCF PATCH POINTS
This is the main control voltage input for the VCF and has characteristics of one volt per octave. This should be
used as your main control input from a keyboard/ controller.
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This is simular to the VCF 1/V input but should be used for external modulation.
This is an audio input, it allows external signals (audio) to be processed by the VCF. Too much external signal will
cause the filter to over-drive or distort.
This is the audio output of the filter prior to modification by the VCA.
V
VC CA AVOLTAGE CONTROLLED AMPLIFIER
VCA CONTROLS
The signal knob controls the audio signal level coming from the VCF into the VCA. The VCA may be over-driven
(clipped) in the range of 5 - 10.
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The VCA is an amplifier which allows its gain to be
altered by a control voltage. The VCA within the MARS
has both logarithmic and linear controls creating unique
contours.

The envelope knob sets the amount of voltage controlled amplification from the envelope generator. Linear and
logarithmic control is available giving unique and unusual amplification contours.
VCA PATCH POINTS
This input allows logarithmic modulation of the VCA by an external source.
This input allows linear modulation of the VCA by an external source ( the usual control input from an envelope
generator).
This is an external input that allows audio and control signals to be processed by the VCA.
This is the output of the VCA, it is also the final output when used as a complete synthesizer.
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The attack knob controls the amount of time it takes the output voltage to reach the
maximum level once the gate is initialised.
The decay knob controls the amount of time it takes the output voltage to fall to the
sustain level once the attack phase is complete, providing the gate has not already
ended.
The sustain knob controls the level of the output voltage until the gate ends.
The release knob controls the amount of time it takes the output voltage to fall to ‘0’
once the gate has ended.
The L.E.D. is a visual indication of ENV activity.
The ENV is a method of generating a control
voltage, the waveshape is created in 4 stages:
Attack, Decay, Sustain and Release which can
be adjusted individually. The output of the
ENV can control any voltage controlled input.
E
EN NV VENVELOPE GENERATOR
ENVELOPE CONTROLS

ENV PATCH POINTS
This is an input which initialises the ENV cycle (eg: the gate output from a keyboard/controller with a minimum
output of 1 volt).
This is the trig/retrig input. A short positive pulse will re-initialise the already gated ENV.
This is the output voltage of the ENV which can be used to control any voltage controlled input.
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SPECIFICATION
VCLFO
Fc Range 0.055 Hz (one cycle per 18 seconds)
33 Hz (33 cycles per second)
Waveforms Positive and negative sawtooth, square and triangle waveforms available
simutaniously 10v peak to peak +/- 5v
VCO
Fc Range 1.5Hz to 16.5KHz Exponential response 1 volt per octave.
Internal Fc Mod Square or triangle +/- 1 octave
Waveform Sawtooth waveform that transfers through square to 2% negative pulse
(no fixed point)
Internal Wave Mod Triangle (VCLFO) envelope. Full positive wave control
Temp Compensation Factory set at 80 degrees for minimal drift.
VCF
Type 24dB per octave low pass ladder filter. Transistors and capacitors
matched at specific temperature with 0% tolerance.
Fc Range 20 Hz to 20 KHz.
Internal mod Square or triangle +/- 4 octaves (from VCLFO).
Resonance Zero to self oscillation.
Envelope Mod +/- 10 octaves.
VCA
Gain Control Internally routed linear or logarythmic control by envelope generator.
ENV
Gate 1v to 12v positive gate.
Trig/Retrig 1v to 12v positive pulse.
Output Voltage Zero to 10v (approx).
Attack Time 5ms to 7.5 seconds.
Decay Time 5ms to 15 seconds.
Sustain Level Zero to 100%.
Release Time 5ms to 15 seconds.
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Burn-In Before final calibration units are burnt-in for a minimum of 96 hours.
Power Requirements UK: 230v AC 50 Hz (220v - 240v).
Export: 115v AC 60Hz (100v - 120v).
Internal Supply +/- 12v DC 90 mA.
AC Voltage Select The MARS has an ‘AC V. SELECT’ switch. It is imperative that this is set correctly. Failure to
do so will void warranty and damage the unit beyond repair.
Warranty The SMS MARS comes with a 12 month (from purchase date) back-to-base warranty, (i.e.
customer must arrange and pay for carriage to and from SMS).
Contact Us Please don’t hesitate to get in touch with us for any enquiry:
Andy Pledger: [email protected]
Tel. [phone]
www.syntheticmusicsystems.co.uk
Thanks To Paula Allen (Web and Manual Design)
Ian at Action Hardware
Bob at Analogue Systems
Steve “synth-genius”
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