Doepfer A-106-1 Xtreme Lowpass/Highpass Filter - Manual (Page 9)

DOEPFER DOEPFER DOEPFER DOEPFER System A-100 X-treme Filter A-106-1
9
4. Controls and In- / Outputs
! CV1: CV1 input
1 Frequ. : manual frequency control
" CV2: CV2 input
2 CV2: attenuator for CV2
§ CV3: CV3 input
3 CV3: polarizer/attenuator for CV3
This group of elements is responsible for the filter
frequency. Knob 1 Frequ. is used to adjust the frequency
manually. Three CV inputs (CV1 !, CV2 ", CV3 §) are
available to control the frequency by external control
voltages (e.g. ADSR, LFO, random, sequencer). The
sensitivity of CV1 is fixed, CV2 is equipped with a normal
attenuator 2, CV3 with a polarizer 3. The neutral position of
the polarizer knob is at it’s center (0). Left from the center
(area marked with a minus sign) the effect of the CV3 is
negative, i.e. an increasing CV3 decreases the frequency.
Right from the center (area marked with a plus sign) it’s
positive, i.e. increasing CV3 increases the frequency.
The control scales of the three CV inputs are non-linear, i.e.
not 1V/octave as CV inputs of many other A-100 modules.
$ LP In: low pass audio input
4 LP Level: low pass audio input attenuator
% HP In: high pass audio input
5 HP Level: high pass audio input polarizer/
attenuator
Socket $ is the low pass audio input (LP In) with the
assigned attenuator 4. Socket % is the high pass audio
input (HP In) with the assigned polarizer 5. This polarizer
can be converted into a normal attenuator by changing an
internal jumper (please refer to page 7 for details).
The HP In % is normalled to the LP In $, i.e. if no plug is
inserted into the HP In % the signal applied to the LP In $ is
also used for the high pass section.
For pure LP function the HP Level 5 has to be set
approximately to it's center position. The best way to find
the neutral positon of the HP control is by hearing. Move the
control until the high pass share disappears in the audio
output signal. As it is a bit tricky to find the neutral position
even a dummy plug can be inserted into the HP In socket
for pure LP applications. In this case the normalling between
the sockets LP In and HP In is interrupted.
Both the LP and the HP audio input are very sensitive. With
standard A-100 signals (e.g. VCO) distortion appears
already at medium settings. But the distortion also depends
upon the clipping and resonance settings.