Doepfer A-121 12dB Multimode VCF User Manual
System a - 100, A-121, Introduction
doepfer
System A - 100
VCF 2
A-121
1
1. Introduction
Module A-121 (VCF 2) is a voltage-controlled multi-
mode filter with a cut-off slope of -12 dB / octave.
Four simultaneous outputs are available, each with
different characteristics: low-pass, band-pass, high-
pass and notch (or band reject).
The cut-off frequency determines the point at which
the respective filter effects appear. The frequency can
be adjusted manually, or by voltage control (Filter
modulation, for instance by an LFO or ADSR). Two
CV inputs are available, whose control voltages are
summed.
Resonance (Emphasis or Q ) can be adjusted
manually, or by voltage control (voltage-controlled
resonance / VCQ), right up to self-oscillation, in which
case it will behave like a sine wave oscillator.
Audio
In
FCV 2
FCV 2
QCV 1
QCV 2
QCV 2
Res.
FCV 1
A-121
MULTIMODE
FILTER
Freq.
Audio Level
Low Band High Notch
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