This is the 1U wide ‘Filter
Core’ version of the Diode SuperLadder. One would normally use
this module in conjunction with external mixers for maximum
control.
This latest version of the classic
Oakley Superladder was redesigned from the ground up to sound
good using diodes.
The circuit is considerably
different from all previous designs and has its own tonal
characteristics I think you will love. It now features a new
switch to select the maximum number of diode rungs in the ladder.
You can now chose between four and five pole filtering – with the
five pole mode giving a steeper roll off and smoother tone.
The Diode Superladder VCF features
both voltage control over frequency and resonance. Unique to any
diode ladder filter is has a variable shape output. This
incorporates a feature first seen on the Oakley Orbital
prototypes. A single pot allows you to vary the output from one (or
two) pole low pass to four (or five) pole low pass via band pass
in the middle.
The Diode Superladder’s output is
what we call ‘Q compensated’. This means that the output volume
will not drop significantly when you turn up the resonance pot.
This design uses two inbuilt VCAs to achieve voltage controlled
resonance without the hassle. At high levels of resonance the
Diode Superladder will self-oscillate across most of the audio
band and thus can be used as a sinewave voltage controlled
oscillator.
The filter core uses transistors
wired as diodes which means it does not clip the signal abruptly
but saturates smoothly. This allows the Diode Superladder to
sound very different depending on the input signal level. When
used with signals below 2V peak the Superladder will sound clean
and bright. However, take your signal levels above 2V peak and it
will start to take on a more strident tone particularly at higher
levels of resonance. Coupled with the variable slope control,
this sensitivity to input level means the Diode Superladder can
produce a wonderful array of different tones.
The voltage controlled filter, or
VCF, may be built as a 1U filter core or as a complete 3U filter
system. The 1U ‘Filter Core’ format is our way of handling filter
modules. Although the 1U module can be used as a filter module on
its own, it is expected that users will make use of external
mixers to control CV and audio levels going into the filter. In
this way, you will be able to have a collection of space saving 1U
filter cores that can be used with any generic mixer module. The
Oakley Multimix is an ideal choice for a handy mixer module.
Power (+/-15V) is provided to the board
either by our standard Oakley 4-way header or Synthesizers.com
header. Current consumption is approximately 35mA per rail.
The PCB is 10.6cm (deep) x 14.3cm
(height). The frequency, resonance, resonance CV depth and shape
pots are normally board mounted for easier construction.
As with all Oakley projects the
PCB is double sided with through plated holes, has solder mask
both sides, and has component legending for ease of construction.
This is the suggested panel design for the
3U version of the Diode Superladder. This is a fully featured
filter module that includes inbuilt CV and audio mixer sections.
Sound Samples
Slow sequence in four stage
mode. Cut off frequency, filter slope and resonance are manually
tweaked.
Faster sequence in five stage
mode. Again cut off frequency, filter slope and resonance are
manually tweaked.
Another sequence, this time
more of a Berlin School thing, with added effects for ambience.
The Diode Superladder as a single width
MOTM format module in a natural finish Schaeffer panel. Note also
the use of the optional Sock4 socket board to help keep the
wiring to the sockets neat and tidy.
Downloads
Diode
Superladder issue 2 Builder’s Guide
Construction
Guide Our handy guide to building
Oakley DIY projects
Parts
Guide Our handy guide to buying
parts for Oakley DIY projects.
Links to schematics are
available to purchasers of the PCB or module and will be sent via
e-mail when the board(s) are shipped.
Use ‘save as…’ button to
download and view the files. IE users need to right hand mouse
click and then choose ‘save as’.
Front Panel database
A Schaeffer front panel can be made for
this module. The database can be found by downloading the
following link:
5U format 1U wide (Filter
Core) module in traditional black
5U format 3U wide (Full
Version) module 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.
Schematics and Projects: Projects
Back home