Doepfer A-188-2 Tapped BBD Module - Manual (Page 12)

DOEPFER System A-100 BBD Module A-188-2
12
)
Single Outputs
The six sockets ) are the "raw" outputs (taps) of the BBD
stages 3328, 2790, 1726, 1194, 662 and 396. These
outputs can be used e.g. for for feedback patching, for
external mixing (e.g. with a voltage controlled mixer) or for
multi-channel applications (e.g. 5.1 sounds).
1
a,
1
b : mix levels/polarities of the BBD taps
3328, 2790, 1726, 1194, 662 and 396
(polarizers)
2
a,
2
b Mix: wet/dry controls for outputs 1 and 2
(
1/2
a are assigned to sub-mixer 1)
(
1/2
b are assigned to sub-mixer 2)
/
Output 1: mixed audio output 1
(
Output 2: mixed audio output 2
This group of elements is responsible for the two mixed
outputs appearing at the sockets / Output 1 and ( Output
2. In the left/ccw position of the knobs 2a/b Mix the original
signal appears at the sockets //(. In the right/cw position of
the knobs 2a/b Mix the internal pre-mix signal composed
from the the six BBD taps with the polarizers
1
a/b appears
at the sockets //(. In the intermediate positions of the
knobs 2a/b Mix a mix of these two signals appears at the
corresponding output socket.
Note: The labelling of the output sockets is wrong. The left
pair of sockets is Output 2, the right pair is Output 1
&
Ext.FB In: external feedback input
6 Feedback: feedback level and polarity control
(polarizer)
This group of elements is responsible for the feedback
functions of the module. Socket & Ext.FB In is the input of
the feedback loop and is normalled to socket ) BBD Out
396. Patching the feedback socket to any of the other single
output sockets another BBD tap can be used for the
feedback function to a obtain different sound. If an external
module is used to control the feedback loop (e.g. a VCA or
VC polarizer) the module has to be inserted between one of
the six sockets ) BBD Out and socket & Ext.FB In. The
feedback control
6
Feedback is a polarizer with the neutral
position at the center. Left from the center the feedback
signal is subtracted from the input signal, right from the
center it's added (negative/positive feedback). The polarity
of the feedback signal leads to clearly audible different
sounds especially at short delay times as different
frequencies are emphasized or attenuated for positive or
negative feedback. For longer delay times ("analog delay"
application) the sound differences are much smaller
In the fully right/cw or fully left/ccw position of the feedback
control
6
the module goes into self-oscillation. As already
mentioned in chapter 2 the result in the self-oscillation state
depends upon the "audio history" (for details please refer to
page 7).