ARP 4075 LPF 36B
The
4075 Filter is a faithful recreation of the 24db low-pass filter found in
late model Arp Odysseys.
The filter topology is almost identical to the Arp 4072
filter module found in later editions of the ARP 2600
synthesizer.
The following
two mp3s are examples of
the 4075 as a self oscillating sine wave generator
being modulated by the Sequencer 17a and a variety
of LFOs,ADSRs and Oscillators.
Self-oscillation1.mp3
Self-oscillation2.mp3
Inputs
1-3
An onboard mixer sums the three inputs together
and the level control knob sets the overall input level to the filter.
Moderate gain settings provide the smoothest sound but higher gain settings
are better for high resonance sounds.
1V/Oct
Input
Exponential converters track
linear voltage input at 1 volt per octave. This input is primarily used for
keyboard
tracking and pitch control of filter in self-oscillation mode.
CV Input 1
Control Voltage input with attenuator
to control the depth of frequency modulation.
When the knob is centered no modulation occurs. Positioning the knob to the
left of zero inverts the incoming voltage (negative) and to the right the
voltage is non-inverted (positive).
CV Input 2
Secondary Control Voltage input with attenuator.
CV inputs are used to control the filters cutoff point.
The most common
input signal would be from an envelope generator or LFO.
Resonance Control
This knob varies the height of the resonant peak at the cutoff frequency of
the filter.
Specifications:
Wide-range lowpass filter with variable-height
resonant peak at cutoff frequency.
4 pole response
24db/oct cutoff slope
Range:Continuously variable from 16Hz-18kHz
Input impedance:
100K ohms
Output impedance: 1k ohms
Control Sens: 1 volt per octave