Synthrotek VCO User manual

VCO Manual
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Table of Contents:
General Info
Quick Start Guide
Important Links
Powering Up your Module
Calibration
Front Panel Controls and Jacks
TUNE
FINE
MOD IN
MOD ATTN
PW IN
PW
1V/O
Triangle Waveform
Sawtooth Waveform
Square Waveform
General Info
The VCO is an analog voltage controlled oscillator with a wide frequency range and 8 trackable
octaves. It uses the Curtis CEM3340 reissue chip, which is famous for its outstanding sound
quality.
Features:
● Simultaneously available triangle, saw and square wave outputs
● Frequency range: 5Hz to 28kHz
● FM input and attenuation control
● PWM input and CV control
● 1V/o input, tracks 8 octaves
Specifications:
● Width: 4HP
● Depth: 53mm
● Power draw:
○ +12V: 42mA
○ -12V: 31mA
Includes power cable and module screws.
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Quick Start Guide
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Important Links
Store Page
Assembly Instructions
Bill of Materials
Powering Up your Module
Turn off your modular system before plugging in your VCO module. Plugging in your module
while the power is on (“hot swapping”) can damage a module. Plug a 10 to 16 pin power cable
into the module and then into your power supply, aligning the stripe of the cable with the
STRIPE indicator on the power supply. Then power it on!
Calibration
If you built the VCO yourself or need to calibrate your module for your system, use these
instructions here to calibrate it.
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Front Panel Controls and Jacks
TUNE
● Coarse tune control. The LED flashes according to the oscillator rate. The combined
range of the FINE and TUNE pots is approximately 5Hz to 28kHz.
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FINE
● Fine tune control. The LED flashes according to the oscillator rate. The FINE pot has a
range of a 9th, or an octave plus one whole step.
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MOD IN
● Frequency modulation input. Synthrotek’s VCO uses linear FM.
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MOD ATTN
● Frequency modulation attenuator. This pot attenuates the signal from the MOD IN jack,
and will only work when the MOD IN jack is patched. The LED flashes according to the
rate of the oscillator plugged into the MOD IN jack. It will not flash if MOD IN is not
patched. When patched, it will gradually become brighter as the pot moves upward. The
brightness will also vary depending upon the strength of the signal patched into the MOD
IN jack. When the MOD IN jack is patched and pot is slid downward to zero, the
oscillator’s frequencies will not be modulated.

PW IN
● Pulse width Input. This input will receive audio and CV signals and will affect the pulse
width of the square wave output. It has a pronounced effect on the square wave, but it
can be used to create a slight pleasant tremolo effect on the triangle and sawtooth when
patched with an LFO. The incoming signal to the PW IN jack is additive to the position of
the PW slide pot.
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PW
● Pulse width. The PW pot changes the pulse width. This primarily affects the square wave
output, and will affect it whether or not the PW IN jack is patched (it does very little with
the sawtooth and triangle waves on its own). When the pot is centered, the square wave
will be symmetrical (50% duty cycle). When the pot moves upward, the duty cycle ratio is
higher; when it moves downward, the duty cycle ratio is lower. The PW pot LED will
gradually become brighter as the pot moves upward.
1V/O
● 1 Volt per Octave input. Accurately tracks 8 octaves when calibrated. Additive to the pot
position.
Triangle Waveform
● Triangle waveform.
Sawtooth Waveform
● Sawtooth waveform.
Square Waveform
● Square waveform.
More questions? Get a hold of us here:
503-417-1130
[email protected]
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