Doepfer A-120 24dB Low Pass 1 - Manual (Page 4)

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