Doepfer A-198 Trautonium / Ribbon Controller - Manual (Page 3)

doepfer System A - 100 Trautonium / Ribbon Controller A-198
3
3. Controls
1 Scale
The position sensor of the A-198 is in principle a
linear potentiometer that is activated whenever a
finger touches the sensor. Consequently the relation
between the position of the finger and the Control
Voltage CV
POS
is linear too (see fig. 1).
Fig. 1: Connection between position, Control Vol-
tage CV
POS
and Scale
The Scale, i.e. the connection between position diffe-
rence and voltage difference, is adjusted with control
1
(see fig. 1).
P If CV
POS
is used to control the VCO pitch
the scale is adjusted with control 1 so that
the position difference corresponds to the
desired spread, e.g. 25 cm for one octave.
2 Hold
This switch determines the behaviour of the position
control voltage CV
POS
if the finger is removed from
the sensor:
In the Off position of the Hold switch the control
voltage CV
POS
drops to 0V as soon as the finger is
removed. If the Gate output " is used to trigger an
Envelope Generator (e.g. A-140, A-141), that controls
the loudness of a VCA or the timbre of a VCF, the
Release time of the Envelope Generator should be
set to zero so that the dropping tone is muted. This is
identical to the behaviour of the Trautonium. Even for
Off : CV
POS
drops to 0V and the Gate output "
turns from high to low. This is the same mode
that was available in the Trautonium.
On : The last control voltage before the finger was
removed is held with an internal S&H circuit.
In this mode the Gate function at output " is
not active (Gate is permanently high). This
mode was not available in the Trautonium.
Ribbon Sensor
CV
POS
Posit ion
Scale