The 14HP wide Oakley Dual VCO, or DVCO, is
two traditional sawtooth core voltage controlled oscillators in
one module sharing a single common 1V/octave input. Each
oscillator features a sawtooth (falling ramp) and variable width
pulse wave output. VCO2 also has an additional triangle wave
output. Except for the triangle wave output, the outputs are +/-5V,
that is, 10V peak to peak. The triangle output is +/-6V, that is,
12V peak to peak.
The pitch of the
two oscillators is controlled with a master fine tune pot on the
front panel, the single 1V/octave CV input, as well as a global
FM input with an associating modulation depth control. VCO2 can
be individually controlled by its own FM input and associating
pot. There are separate three position octave switches for each
VCO. VCO2 also features an individual tune control that covers
just over one octave.
VCO2’s frequency
can be hard synchronised to VCO1 by a front panel switch.
Individual pulse
width controls are available for each oscillator. The middle
position on the pot gives a square wave from the respective pulse
output. At each end of the pot’s travel the pulse output will be
silent. Pulse wave modulation is available for each VCO
separately and each has its own depth control.
Current draw is
approximately +75mA and -85mA at +/-12V.
The PCB set
The DVCO module comprises
of two printed circuit boards (PCBs) connected together with
seven 0.1 (2.54mm) single in line (SIL) headers and sockets.
The four layer main board on the rear of the module houses the
power input and conditioning, the two VCO cores, and exponential
convertors. The two layer pot board has the pots, switch, and
sockets that are attached to the front panel, as well as the CV
processing circuitry for pitch and pulse width, and voltage
references. The main board is a four layer design, while the pot
board is a two layer design. Each board is the same size; 68 mm x
107 mm.
The
majority of the components are surface mount parts. The ICs are
SOIC, while the resistors and surface mount capacitors are 0805.
Project Downloads
Dual VCO issue 2 Builders Guide
Dual VCO issue 1 Builders Guide
Construction
Guide Our handy guide to building
Oakley DIY projects
Parts
Guide Our handy guide to buying
parts for Oakley DIY projects
Schematics are only available
to purchasers of the PCBs and will be sent via e-mail when the
boards are shipped.
Front Panel database
A Schaeffer front panel can be made for
this module. The database can be found by downloading the
following link:
14HP Eurorack
format in natural silver
To read, edit and print these
files you will need a copy of ‘Frontplatten Designer’ from Schaeffer. Panels can be ordered via the program using its
secure online ordering system.
Schaeffer are based in Berlin, Germany and
can send panels to anywhere in the world. Delivery to the UK
normally takes around ten days. For North American users you can
also order your Schaeffer panels from Front
Panel Express.
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