C101 OTA LowPass Filter MKII
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The C101 OTA Lowpass lter is a four pole low pass lter
( 24db/octave ) based on four cascade OTA-stages. In this MKII
version a new 6db output has been added expanding the
sonic possibilities of this lter. This OTA lter can be one found
in classic synthesizers like Roland Jupiter 8 , Roland System
100m, Roland SH-1, SH-7, SH-101, Roland System 700 , Jen
SX1000 and many more.
The C101 has been redesigned adding new features and
improving other presents on the original design. The main
changes / improvements are :
- A new rst order output with a 6db / octave response.
With high resonance this output will sound almost like a
bandpass lter.
- A dedicated modulation input for envelopes. This
input has a 0,66 V/Octave response expanding the modulation
range to 7,5 octaves using the typical 5V envelope. In case you
use10V envelopes the input response can be changed to
1V/Octave with a jumper located on the back of the module.
An inverter switch has been added to easily invert the input
signal.
- A better gain compensation circuit for the 24db
output. Not more volume drop when you turn up the
resonance.
- An attenuverter has been added to the resonance
modulation input.
- Better temperature compensation.
At high resonance settings the lter will start to oscillate and it
can be used as a sine wave oscillator. The tracking is perfect
over 5 octaves.
C101 MKII main characteristics
- Two lter outputs with 6db and 24db response
- Temperature compensated
- Dedicated envelope input with 0.66V / Octave response and
inverter
- Filter self oscillate and can be used as VCO ( 1V/Octave )
- Voltage controlled resonance
- Two audio inputs one with attenuator
