Controls And In- / Outputs - DOEPFER SYSTEM A - 100 Bedienungsanleitung

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4. Controls and In- / Outputs

2
Man.: manual vactrol resistance control
!
CV In: control voltage input
1
CV: polarizer for CV input
This group of elements is responsible for the current vactrol
resistance. Knob 1 Man is used to adjust the vactrol
resistance manually. Turning this knob clockwise reduces
the vactrol resistance and lights up the display LED
CV input ! is available to control the the vactrol resistance
by an external control voltage (e.g. LFO, envelope follower,
random, ADSR, keyboard CV, sequencer, theremin, ribbon
controller, foot controller, Midi-to-CV, ...). The CV input is
equipped with a polarizer. In principle a polarizer is an
attenuator, but in contrast to a normal attenuator it enables
both positive and negative attenuations (i.e. amplifications in
the range -1...0...1). Negative attenuation means that the
signal is inverted (please refer to the manuals of A-133 CV
Polarizer or A-138c Polarizing Mixer for details). The middle
position of the polarizer control corresponds to full
attenuation (or amplification = 0). This is the same as the
fully counterclockwise position of a "normal" attenuator. The
fully clockwise position of the polarizer corresponds to
amplification +1 (i.e. the signal passes unchanged), the fully
counterclockwise position corresponds to amplification -1
(i.e. the signal is inverted).
System A-100
"
"
3
The sockets
two vactrols of each sub-unit. In contrast to most other A-
100 sockets these sockets are not grounded, i.e. the two
terminals of the vactrol are connected to the two terminals of
3
. A
the socket in question. The resistance of the two vactrols of
each sub-unit changes simultaneously. The reason is that
for some applications two simultaneously changing resistors
are required (e.g. for some filter circuits).
The LED
LED indicates a high resistance, a bright LED a small
resistance. The minimum resistance range for each vactrol
is about 1 kΩ (fully bright LED) to 500 kΩ (completely dark
LED) but the actual resistance range varies a bit due to the
vactrol tolerances (minimum value 500 Ω ... 1 kΩ at fully
bright LED, maximum value 500 kΩ ... 2 MΩ at completely
dark LED). For more general details about vactrols please
look
www.doepfer.com.
Universal Vactrol Module A-101-9
a VAC1: vactrol 1 connector
b VAC2: vactrol 2 connector
VAC control: LED display
" "
a and b make available the terminals of the
3
displays the current vactrol resistance. A dark
at the Vactrol basics page on our website
5