Doepfer A-120 24dB Low Pass 1 - Manual

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