AS SPAWN User manual


CONTENTS
INTRODUCTION
VCLFO
VCO
MIDI - CV MOD VCA
VCF
SOURCE MIXER
VCA
ENV
MIDI - CV
SPECIFICATION
BLANK PATCH CHARTS
ISOLATION PATCH
INTERNAL SIGNAL ROUTE
INTERNAL MODULATION ROUTE
1
2-3
4-6
7
8-9
10-11
12-13
14-15
16-19
20-21
22
23
24
24

INTRODUCTION TO SPAWN
SPAWN is a monophonic (one voice) Quasi modular rack synthesizer. It’s principle sound source the Voltage
Controlled Oscillator (VCO) generates a variable waveform along with two sub squarewaves and a white noise
source, these signals can be mixed and introduced into the resonant 24dB per Octave low pass ladder filter
(VCF). This stage is followed by a Voltage Controlled Amplifier (VCA). Both the VCF and VCA can be controlled
by the four part multi function Envelope Shaper. A Voltage Controlled low frequency Oscillator (VCLFO) is provided
for frequency and waveshape modulation.
SPAWN also includes a performance VCA (MIDI - CV MOD VCA) this will accept both audio and control signals
and can be controlled by both a control voltage or the internal high performance MIDI - CV convertor.
All signal and modulation routes can be isolated (see Isolation Patch pg 23) allowing for true modular synthesis.
SPAWN is provided with 37 3.5mm Jack sockets to allow signal and modulation patching.
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2
V
VC
CL
LF
FO
OVOLTAGE CONTROLLED LOW FREQUENCY OSCILLATOR
The VCLFO is a wide range oscillator (usually operated in the non audio range)
used to modulate control inputs, e.g: used for vibrato, tremolo and trill. It is internally
routed to the VCO and VCF (see INTERNAL SIGNAL ROUTE page 3).
Four waveforms are simultaneously available and the Rate can be altered using
the linear CV socket.
LFO CONTROL
The Rate knob controls the speed of the modulation waveform.
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.

3
This output gives a squarewave output of +/-5 volts.
This output gives a trianglewave output of +/-5 volts.
This gives linear control of the VCLFO rate, e.g: from keyboard or envelope.

4
V
VC
CO
OVOLTAGE CONTROLLED OSCILLATOR
The VCO is the primary sound source within SPAWN.
It creates the raw waveform which is then processed and
modified by the other synthesizer circuits.
SPAWN contains a temperature compensated oscillator,
conforming to the industry standard logarithmic IV/OCT
response. For ease of control an internal patch from the
Midi/CV interface has been routed to a CV input of the
oscillator, it by passes the Glide control so that the Midi
keyboard controls the level of the Glide. This internal
route can be isolated using the Midi routing switch in the
Midi section.
FREQUENCY CONTROL
1A. In the ‘-2’ position the Tune knob controls the initial frequency of 16Hz by +/- one octave.
1B. In the ‘0’ position the Tune knob controls the initial frequency of 64Hz by +/- one octave.
1C. 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).

5
The CV socket is the main IV/OCT control input for the VCO. This input will accept +/- control voltages and should
be your control input from a CV keyboard/controller such as the A.S French Connection, Sorceror or Demon when
used in the analogue mode. With the ‘Glide’ knob turned to the ‘F’ position (fast) no glide will be present. As the
knob is turned clockwise a slewing of the INPUT voltage will increase. This glide control is also known as
‘Portamento’ or ‘LAG’. If the Midi Convertor is being used internally this input can still be used, Midi generated
CV’s are not routed through the Glide control.
The Pitch Mod Socket and associated Amount Pot is another method of controlling the frequency of the Oscillator.
The Amount Pot also acts as an Invertor so that positive and negative frequency sweeps can be achieved from a
Positive Control Voltage. For instance the envelope sends out 0 to 9.5 volt, if the ENV OUT was patched to the
PITCH MOD INPUT in the full ‘+’ position the frequency of the VCO will increase by 9.5 Octaves. However with
the CONTROL knob in the full ‘-’ position the frequency of the VCO will decrease by 9.5 Octaves. Many control
VOLTAGE sources are available on a synthesizer both + and - AC or DC, so many types of frequency modulation
and sweeping is easily achieved. The closer the knob is to the ‘O’ position the smaller the amount of control.
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.

WAVE SHAPING
The Wave knob controls the initial wave shape from the VCO. In the anti-clockwise position a sawtooth 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 5% 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
waveshape. Pulse width modulation can be created using this method.
The Wave Mod socket and associated Amount pot is the way of externally controlling the waveshape generated
by the VCO. The Amount pot also acts as an invertor. So that the initial wave shape can be swept both positively
and negatively. For example the wave can be converted to a pulse wave using a positive control voltage and
having the amount knob turned clockwise (be aware of voltage level and amount knob position) like wise using a
positive control voltage but with the control knob turned in the negative position a pulse wave can be converted to
a sawtooth. This is a very important control and learning how to use it along with what to use it with will create
very unusual waveshapes.
This is the unmodified output of the VCO and has an output voltage of +10v ( in mode) as it concerts to the
5% pulse the output will have a +/- voltage of 10 volts when the sawtooth component of the wave shape has been
removed the square/pulse wave will be approx - 10v.
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A
The Midi-CV Mod VCA is a performance orientated VCA ,
there are two ways of controlling this VCA. The Midi control
input is routed to the Midi controlled Mod wheel output
(this may be isolated). Although primarily designed to allow
modulation control from midi this versatile VCA can also be
controlled by an analogue CV patched to the CV socket.
This socket is the control input to open the VCA when used in the CV analogue mode. It can be used even if the
internal Midi route is active.
This socket is the signal input to the Mod VCA. Audio and control voltages can be accepted by this input.
Example 1.
Awaveform from the VCLFO coming into the signal input can have its level controlled by an analogue voltage by
the CV this variable level control waveform available at the out socket could then be used to modulate a VCO or VCF.
Example 2.
An audio waveform could be sent to the signal input of the VCA as the CV is increased, the output waveform
level would increase patched to the ext sig in the VCF, a performance control could increase the level of the external
signal into SPAWN.
Two outputs are available from the Mod VCA simultaneous control of VCO pitch and VCF frequency is available.
*Note only Midi is pre-routed, all signal in’s, CV in’s and outputs must be made using the patch sockets.

8
V
VC
CF
FVOLTAGE CONTROLLED FILTER
The VCF in SPAWN is a low pass 24dB/oct transistor
ladder filter. It has the ability to attenuate/eliminate
frequencies above the cut off frequency point. This type
of filter is associated with the classic American ‘FAT’
analogue sound.
The Frequency knob (full name cut-off frequency) controls the point at which attenuation begins. Frequencies
above the cut-off frequency point are attenuated at 24dB/oct.
The Resonance knob is used to accentuate frequencies around the cut-off point, as the resonances increases the
filter will begin to ring and will self oscillate at high resonate settings producing a sinewave (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.
This is the main control voltage input for the VCF and has control characteristics of IV/OCT.An internal patch is
provided from the Midi controller. Allowing the filter to ‘track’ the keyboard, as with other pre-patched Midi routing
this can be isolated using the ‘Midi Routing’ switch in the Midi section. Whether the Midi pre-patch is active or not
the CV1 socket can be used to control the VCF frequency.
The CV2 socket and associated amount pot is another method of controlling the frequency of the filter.
The Amount pot also acts as an invertor so that positive and negative frequency sweeps can be achieved from
a positive control voltage
Example: If a keyboard generated control voltage was applied to the CV2 socket and the amount pot was turned
approx 95% in the clockwise direction as the keyboard is played the filter would track the keyboard with the
IV/OCT characteristics. As the notes are played higher up the keyboard so the filter frequency would increase, if
the amount knob is turned approx 95% counter clockwise again the filter would track but at -IV/OCT, effectively
the higher you play up the keyboard so the filter would decrease.
This is the audio output of the filter prior to modification by the VCA.
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The source mixer is the point at which all internal/external
audio signals can be mixed prior to being processed by
the VCF.
The Signal knob controls the audio signal level coming from the VCO into the VCF. The filter may be over-driven
in the range of 7 -10.
The Sub Octave Generator is a means of creating a squarewave either 1 or 2 octaves lower than the initial
frequency of the VCO. If the control knob is turned anti clockwise a squarewave 1 octave below the VCO
waveform is introduced into the VCF.
If the control knob is turned clockwise a squarewave 2 octaves below the VCO waveform is introduced into the
VCF. The waveshape generated by the VCO will not change the shape of the sub oscillator waveform.
The squarewave 2 octaves lower than the VCO is available at the Sub-2 out socket unatenuated.

The Noise Generator in SPAWN generates white noise. White noise is a signal that contains all the audio frequencies
in equal amounts but has no recognisable pitches or tones the knob is a level control of noise signal being
introduced into the VCF.
Unatenuated and unfiltered noise is available at the Noise Out Socket.
The Sig In socket and associated Level knob is the point at which external audio signals can be introduced into
SPAWN. These signals can then be modified by the VCF if required.
11

12
V
VC
CA
AVOLTAGE CONTROLLED AMPLIFIER
The VCA is an amplifier which allows it’s gain to be altered by a control voltage.
The VCA in SPAWN has both logarithmic and linear controls creating unique contours.
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 7 -10.
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.

13
This input allows linear modulation of the VCAby an external source (the usual control input from an envelope generator).
This input allows logarithmic modulation of the VCAby an external source.
This is an external input that allows audio and control signals to be processed by the VCA.
This is the output of the VCA, as it is also the final output when used as a complete synthesizer a 1/4” socket is
duplicated on the rear panel for convenient patching to your mixer.

14
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.
In addition SPAWN’s envelope has an auto repeat function allowing
auto envelope contours.
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.

15
This is the output voltage of the ENV which can be used to control any voltage controlled input.
The Mode switch controls the type of contour generated by the envelope. With the switch in the centre position
‘ADSR’ the envelope generates the standard 4-part ADSR envelope on initiation of a gate. There are also 2 auto
repeat two part envelope controls, Attack - Decay. In the gated repeat mode the envelope will repeatedly cycle
through the A - D parts of the envelope while a gate is present. In the auto repeat mode the envelope will
continuously repeat the A + D parts of the envelope without a gate present. In both of these modes the sustain
and release controls are non functioning.
This is an input which initialises the ENV cycle (e.g: the gate output from a keyboard/controller with a minimum
output of 1 volt).
Midi is internally routed to the gate input allowing easy control from a Midi - Master keyboard/controller.
As with other internally routed Midi controls this can be isolated using the switch in the Midi section.
This is the trig/retrig input. A short positive pulse will re-initialise the already gated ENV.

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The Midi Controller in SPAWN is a high spec Midi to CV convertor.
Having many functions found on the A.S. RS330 module. Through careful
design this midi convertor can not only control many functions on
SPAWN but it can also control other analogue synthesizers that do not
have Midi built in. For ease of use 5 control routes can be pre-patched to
SPAWN allowing instant playability straight from the box
These two sockets are identical
outputs of the IV/OCT control voltage
from the Midi-CV Convertor.
1/ CV to VCO
Note that this internal patch by-passes the Glide control on SPAWN. If Glide is required when using Midi,
Midi controller no.65 must be activated, and rate of Glide controlled by Midi controller 05 (portamento).
2/ MOD Wheel.
To the Midi-CV MOD VCA. Using the MOD Wheel function on your keyboard/controller the Midi CV MOD VCA can be operated.
3/ CV to the VCF.
This is a non attenuated control input to VCF the filter will track the keyboard/controller at IV/OCT.
4/ Expression.
In addition the cutoff frequency of the VCF can be controlled by Midi controller no11 (expression) this is a powerful
function of SPAWN allowing for realtime manipulation of the filter.
5/ Gate to the Envelope Shaper.
This will cause the envelope to operate (controlling the VCF and VCA). (Note on note off from the Midi kb/controller).
With the switch in the ‘isolated’ position none of the forementioned patches are made. Unless externally patched
SPAWN will not respond to Midi.
*Note whether the Midi routing switch is in internal or isolated mode all the Midi-CV functions are available on the
10 sockets in the Midi section.
The Midi Routing switch controls the internal routing
from the Midi-CV Convertor to five control inputs with-
in SPAWN. With the switch in the ‘Internal Routing’
position the following internal patches are made.
16

This socket provides the output for the Midi generated gate. When no key is pressed on the controlling keyboard
no voltage appears at this socket, when a key is pressed (anywhere) on the keyboard approx 10 volts will be
available at this socket. It remains at this level while the key is held and drops back to OV on release of the key.
This ‘gate’ initialises the envelope generator.
This switch controls the type of keyboard triggering response.
Single.
Anew trigger is produced only when all previous notes have been released. This causes the pitch of the Oscillator
to change but the envelope will not re-trigger.
Multiple.
Atrigger is produced every time that you press a lower note, whether or not previously held higher notes have
been released. This causes the pitch of the Oscillator to change and the envelope to re-trigger.
This socket provides the output for the midi generated trigger when a key is pressed on the Midi keyboard a
pulse of approx 10 milliseconds with a voltage of 10v is generated. This trigger can re-initialise an already gated
envelope.
This socket provides a control voltage output relative to the velocity generated by the Midi master
keyboard/controller.
This socket provides a control voltage output relative to the after touch generated by the Midi master
keyboard/controller.
This socket provides a control voltage output relative to the Mod Wheel (Midi CC no1) generated by the Midi
master keyboard/controller. There is an internally routed patch (see Midi routing switch note 2).
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18
This socket provides a control voltage output relative to the breath controller (Midi CC no2) generated by a Midi
controller. This is a bi-polar controller e.g it can produce +ve and -ve voltages in the range of +/- 5volts.
This socket provides a control voltage output relative to expression (Midi CC no11) this is assignable Midi function
generated by a Midi controller. This is a bi-polar controller e.g it can produce +ve and -ve voltages in the range of
+/- 5 volts. There is an internally routed patch (see Midi routing switch note 4).
This socket provides the output for the Midi generated s-trig, essentially this is an inverted gate signal, when no
note is played on the Midi keyboard the s-trig socket has 10 volts at its output but when a key is pressed this
voltage drops to zero volts, this output can drive an envelope requiring a gate for inversion effects but is primarily
designed to initialise the envelope shapers on early Moog synthesizers when used as a Midi to CV convertor.
TM
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