The issue 4 Noise/Filter front panel
The Oakley Noise and Dual Filter module is
used to generate non pitched sounds such as wind, surf and other
ethereal sounds. It can also be used as a sound source for
percussive sounds like cymbals and snare drums.
Two types of noise output are provided.
White noise which when unfiltered sounds like gas escaping, and
pink noise which sounds more like a big waterfall. The module’s
pink noise circuitry comprises of a complex cascade network
designed to replicate the -3dB/octave low pass response that true
pink noise requires.
The module also gives a very low frequency
output or infra-red signal. This can be heard as a series of
random thumps when listened to, but it is actually a randomly
varying output voltage changing all the time, sometimes quickly
and sometimes hardly at all. Fascinating to watch when it
controls an LED, but it comes into its own when controlling
filter cut-off on an otherwise static sound.
This module also features two separate and
quite unusual voltage controlled one pole filters; one high pass
and one low pass. A one pole filter produces a gentle -6dB/octave
roll off for natural sounding noise effects. These are internally
normalised to the noise generator’s output, but may also be used
separately to process other sound sources too.
The two filters are both voltage controlled
so the cut off frequency may be controlled by an external CV
signal from, perhaps, an ADSR, LFO or midi-CV convertor. A front
panel pot and three way switch allows you to control the depth of
the modulation for either or both filters. The pot is a ‘reversible
attenuator, so you are able to control not only the depth of the
modulation but also the polarity.
The noise source is true analogue, a
reverse biased PNP transistor.
Power (+/-15V) is provided to the board
either by our standard Oakley 4-way header or Synthesizers.com
header. Current consumption is approximately 30mA per rail.
The PCB size is 102mm (high) and 114mm (deep).
The issue 4.1 PCB behind a natural finish
Scheaffer panel. Note the use of the optional Sock8 board to make
wiring the socket field much easier.
Sound Samples
White Noise
Pink Noise
Low pass filtered noise
High pass filtered noise
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 PCBs and will only be sent via e-mail when
the board(s) are shipped.
Front Panel database
A Schaeffer front panel can be made for
this module. The databases can be found by downloading the
following links:
5U format in
traditional black
To read these files you will need
a copy of ‘Frontplatten designer’ from Schaeffer. The program also features on-line ordering, so its
now even easier 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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