Internal Settings; Priority Mode Setting; Channel Settings; Microphone Or Line Input - Bosch LBB 1920 Installation And Operating Manual

Plena universal pre-amplifier
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Plena Universal Pre-amplifier | Installation and Operating Manual |
2

Internal settings

LINE 4
CINCH
XLR
CN106
MIC
LINE
CN108
CN107
Figure 2.1

2. 1 Priority mode setting

The priority mode can be set with jumper JP109 to serial or blocking mode. You can activate the mixing mode for
channel 1 to 4 with jumpers JP111 to JP114. The jumper JP110 enables or disables the priority override contact for
the 4 input channels. This contact is available on the Master Mic output to pass through priorities.
-
Serial mode(default) : Channel 1 has the highest priority and channel 4 the lowest.
-
Blocking mode
-
Mixing mode

2.2 Channel settings

2.2.1 Microphone or Line input

If you connect a microphone to an input channel, the switch (S101 to S104) must be in the Mic position. This setting
activates the Phantom power supply. If you connect a line level source the switch (S101 to S104) must be set in the
line position.

2.2.2Mic/Aux input selection

If you use the 5-pole DIN or the 3-pole XLR input of a channel, the corresponding jumper (JP102, JP104, JP106 or
JP108) must be in the MIC position. If you use the Cinch input the jumper must be in the AUX position.

2.2.3Speech filter on/off

Each channel has a speech filter that can be enabled or disabled with the corresponding jumper (JP101, JP103,
JP105, and JP107). The speech filter improves speech intelligibility by cutting off the lower frequencies.
Bosch Security Systems | 2003-09 | 3922 988 99482en
LINE 3
DIN
CINCH
XLR
S104
MIC
LINE
CH4
SPEECH CH3
SPEECH CH4
OFF
ON
JP108
AUX
MIC
AUX
INPUT
CH4
INPUT
JP110
OVERRIDE RELAY
OFF
ACTIVE
20-1
4 E 3 2 E 1
: The first activated input channel has the highest priority and blocks all other channels.
: The channel is mixed to the master output irrespective of priority.
Internal settings
LINE 2
DIN
CINCH
XLR
S103
CH3
JP105
OFF
ON
JP106
MIC
CH3
4 E 3 1 B 2
LINE 1
DIN
CINCH
XLR
S102
MIC
LINE
CH2
SPEECH CH2
JP103
OFF
ON
JP104
AUX
MIC
INPUT
CH2
PRIORITY
JP109
SERIAL
BLOCK
OFF
ON
JP114
CH-4
JP113
CH-4
JP112
CH-4
JP111
CH-4
MIXING
B
E 1 2 3 4 M
en | 9
DIN
S101
MIC
LINE
CH1
SPEECH CH1
JP101
OFF
ON
JP102
AUX
MIC
INPUT
CH1

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