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V

V

C

C

F

F

VOLTAGE 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).

Summary of Contents for SPAWN

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Page 2: ...TION 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 ...

Page 3: ...er 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 Al...

Page 4: ...uted 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 wi...

Page 5: ...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 ...

Page 6: ... 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 pos...

Page 7: ...f 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 po...

Page 8: ... 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...

Page 9: ...Mod VCA Audio and control voltages can be accepted by this input Example 1 A waveform 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 th...

Page 10: ...n 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 f...

Page 11: ...o 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 ...

Page 12: ...r 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 th...

Page 13: ...gnisable 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 ...

Page 14: ...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 ...

Page 15: ... allows logarithmic modulation of the VCA by 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 ...

Page 16: ...ob 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 am...

Page 17: ...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 allo...

Page 18: ...on 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 Envel...

Page 19: ...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 envel...

Page 20: ...oller 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...

Page 21: ...h you wish to control MIDI THRU Any MIDI data received at SPAWN S MIDI IN socket will be echoed by the MIDI THRU socket thus allowing you to connect SPAWN in a daisy chain of MIDI devices MIDI CHANNEL SELECTOR The MIDI channel selector offers sixteen positions marked in hexadecimal fashion from 0 to F Use a small tool such as precision screwdriver to choose the MIDI channel on which SPAWN recieves...

Page 22: ...se no fixed point Internal Wave MOD Triangle VCLFO envelope Full positive wave control Temp Compensation Factory set at 80 degrees for minimal drift Source Mixer Sub Octave Generator 1 and 2 octaves Noise Generator white noise 10v peak to peak 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 Interna...

Page 23: ...0 5v MOD Wheel 0 5v Breath and 5v Expression and 5v S Trig 10 0v 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 SPAWN 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 be...

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