The Oakley Dual-LFO
is a single width 5U high module that features two highly useful
low frequency oscillators.
This is an updated version of the low
frequency oscillator from a classic Japanese vintage analogue
synthesiser. It features two output waveforms, triangle and pulse.
But, the design also incorporates a ‘Shape’ control that affects
the rise and fall times of the triangle waveform, and mark-space
ratio of the pulse waveform. Therefore, you can get sawtooth and
reverse sawtooth from the triangle output by using the Shape
control.
The Dual-LFO uses an integrated FET switch
IC to enhance the original design. It also allows the use of
waveform synchronisation. This is where the output waveform is
reset back to zero when a SYNC pulse arrives from another module
(or the other half of the Dual-LFO). If the SYNC pulse is the
GATE output of a midi-CV convertor, then you can use the Dual-LFO
as a linearly sloped repeating envelope generator.
A range switch on each LFO allows for a
wide range of low frequencies to be generated.
The module
accommodates either our standard Oakley/MOTM power header or a
Synthesizers.com power header. The current draw is around +30mA
and -10mA.
The board size
is 84mm (deep) x 126mm (high). As
with all Oakley projects the PCB is double sided with through
plated holes, has tough solder mask both sides, and has bold
component legending for ease of construction.
Specifications
Operating
frequency: 0.3Hz – 30Hz (fast), 0.03Hz – 3Hz (slow)
Pulse
output level: 0V (low state), 9V (high state)
Triangle
wave output level: +/-4.5V
The
prototype Dual-LFO behind a natural finish MOTM format panel.
Note the optional Sock6 PCB that holds the six 1/4″ sockets
and makes the build much quicker and easier.
Project Downloads
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 PCB and will be sent via e-mail when the
board(s) are shipped.
Front Panel database
A Schaeffer front panel can be made for
this module in either traditional black or natural finish. The
databases can be found by downloading the following links:
5U format 1U wide Dual-LFO
module in traditional black
5U format 1U wide
Dual-LFO module in natural finish
To read these files you will need
a copy of ‘Frontplatten designer’ from Schaeffer. The program also features on-line ordering, so it’s
easy to buy your panels from Scheaffer.
The company are based in Berlin in Germany
and will send out 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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