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Specifications

Width: 9 HP

Supply voltage: +12V/-12V (Eurorack 10-pin header)

Current draw:

+12V: 35 mA

-12V: 35 mA

5V: unused, 0 mA

CV inputs: 2x 0V to 10V usable, -12V to 12V absolute

Connecting SCRAT to Eurorack power

Connect a 10 pin Eurorack power cable to the 2x5 power header on the
back of the module. There is an arrow indicator next to the word
STRIPE on the circuit board. Unsurprisingly, the red stripe side of
the cable goes on the side that says STRIPE. The module (and your
power supply) is protected in case you should ever connect it the
wrong way around, but it won’t turn on if you do.

Module Function

SCRAT is a 2-pole (-12 dB/Octave) multimode Steiner-Parker filter
(VCF) that offers high-pass and low-pass modes and is quite aggressive
sounding.

In addition to the built-in sound-shaping possibilities, the user can
optionally

modify

the

filter’s

character

by

plugging

passive

electronic components like diodes, capacitors or resistors into either
or both of two modifier ports on the front panel, or special pre-made
cartridges that contain small circuits made up of such components.

SCRAT also includes a pre-filter drive circuit that can be used to

further shape the sound.

Summary of Contents for SCRAT v1.1

Page 1: ... multimode Steiner Parker filter with a twist You can change the resonance response by plugging in components like diodes capacitors or resistors directly to the front panel A set of preset cartridges is also available which gives you instant access to a variety of filter sounds ...

Page 2: ...is protected in case you should ever connect it the wrong way around but it won t turn on if you do Module Function SCRAT is a 2 pole 12 dB Octave multimode Steiner Parker filter VCF that offers high pass and low pass modes and is quite aggressive sounding In addition to the built in sound shaping possibilities the user can optionally modify the filter s character by plugging passive electronic co...

Page 3: ...nents or cartridges are currently inserted into the modifier ports see below RESO This changes the filter s resonance Q factor In the fully counterclockwise position there is no resonance Around the 10 o clock position the filter will start to self resonate depending on the other controls settings with the intensity increasing up to the fully clockwise position FREQ This determines the cutoff freq...

Page 4: ...lso slightly adjust the cutoff This is inherent to the Steiner Parker filter design If you need 1V Octave tracking throughout your track or performance do not change the RESO setting once a satisfactory tracking has been established Control Voltage CV Inputs Both CV inputs expect signals within the 0V to 10V range Don t worry about supplying a higher or lower CV though It will not harm the module ...

Page 5: ...tors unless you know exactly what you re doing Reverse voltage may make them explode violently You may use them with the positive leg on one of the P ports and the negative leg on one of the G ports but it is better to avoid them completely Large value bipolar ceramic capacitors are easily available and should be used instead The use of active components like transistors could result in unexpected...

Page 6: ...s should go to ground in parallel connect either of them to one of the P ports and both of their other legs to a G port Accidentally shorting from P or S to ground will not harm your component or the module as the circuit is protected by a 1k resistor to ground Modifier Port Patch Ideas Diodes or LEDs work well in parallel especially if using two different diode types while their polarities are op...

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