A-120
VCF 1
System A - 100
doepfer
4
Fig. 2:
How resonance affects the response of a low
pass filter
4. In / Outputs
!
CV 1
Socket CV 1 is the filter’s standard
voltage control
input
, and works on the 1V / octave rule, like the
VCOs.
If you patch a modulation source (eg LFO, ADSR) to
this input, the cut-off frequency of the filter will be
modulated by its voltage: ie., the sound color changes
according to the voltage put out by the modulator.
If you use the VCF as a sine wave oscillator, connect
the pitch CV into this socket. Do the same if you want
the filter’s cut-off frequency to track exactly with the
pitch of a note.
"
CV 2 •
§
CV 3
Sockets CV 2 and CV 3 are also
voltage control
inputs for the filter.
Unlike CV 1, you can control the
level of voltage - the intensity of modulation effect on
the filter - with attenuators
2
and
3
.
$
Audio In
This is the filter’s
audio input
socket
.
Patch in the
output from any sound source (eg. VCO, noise gene-
rator, mixer).
%
Audio Out
Filter output
%
sends out the filtered signal.
fc
Resonance
Frequency
➨
➨
➨
➨
0 db
