doepfer
System A - 100
VCF 1
A-120
1
1. Introduction
Module
A-120 (VCF 1)
is a
voltage controlled low-
pass filter
, which filters out the higher parts of the
sound spectrum, and lets lower frequencies pass
through.
The
Cut-Off Frequency
determines the point at which
filtering takes effect. You can control this manually, or
by voltage control (
filter modulation
, for instance by
an LFO). Three CV inputs are available, and the sum
of the voltages from these affects the filter cut-off.
VCF1 is a co-called "
transistor ladder
" design, with a
cut-off slope of -24 dB/octave, as in various Moog
synthesizers. That’s what gives it its classic, legendary
Moog sound.
Resonance
(or Emphasis) is adjustable all the way up
to self-oscillation - in which case the filter behaves like
a sine wave oscillator.
CV 1
Resonance
CV 3
CV 2
A udio In
Lev el
Audio
Out
CV 2
Frequency
A-120
VCF 1
CV 3
