Bosch LBB 1920, Installation And Operating Manual

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Bosch Security Systems | 2003-09 | 3922 988 99482en
Plena Universal Pre-amplifier | Installation and Operating Manual | en | 9
2 Internal settings
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 : The first activated input channel has the highest priority and blocks all other channels.
- Mixing mode : The channel is mixed to the master output irrespective of priority.
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.
Internal settings
4 E 3 2 E 1 4 E 3 1 B 2
B
CH-4
MIXING
OFF
PRIORITY
JP109
JP114
SERIAL BLOCK
JP113
JP112
JP111
ON
E 1 2 3 4 M
SPEECH CH1
JP101
OFF
S101
JP102
CH1
MIC
LINE
ON
AUX
INPUT
MIC
CH1
SPEECH CH2
JP103
OFF
JP104
ON
AUX
INPUT
MIC
CH2
SPEECH CH3
JP105
OFF
JP106
ON
AUX
INPUT
MIC
CH3
SPEECH CH4
OFF
JP108
ON
AUX
INPUT
MIC
CH4
JP110
OVERRIDE RELAY
S102
CH2
MIC
LINE
S103
CH3
MIC
LINE
S104
CH4
OFF ACTIVE
CN107
20-1
CN108
CINCH XLR
LINE 4
DIN
CN106
MIC
LINE
CH-4
CH-4
CH-4
CINCH XLR
LINE 3
DIN CINCH XLR
LINE 2
DIN CINCH XLR
LINE 1
DIN