Bosch F.01U.505.591 Datasheet
Communications Systems | LBB 1925/10 Plena System Pre-Amplifier
LBB 1925/10 Plena System Pre-Amplifier
Six-zone system pre-amplifier, with single or dual
▶
channel operation
Two input channels for call stations
▶
Universal input for microphone/line, with speech
▶
optimized tone control
Three inputs for BGM selection and music optimized
▶
tone control
Front panel zone selection for BGM and call station
▶
zone selection for calls
PC and trigger inputs for automated calls, alarm
▶
tones and chimes to selected zones
The Plena system pre-amplifier is a versatile, highperformance unit with call and mono BGM (background
music). It fulfills a wide variety of public address
requirements at a surprisingly low cost. It can provide
dual channel operation for simultaneous calls and BGM
for up to six different zones, using two Plena amplifiers.
Functions
The call channel provides two inputs for the Plena call
stations, LBB 1941/00 (all-call) or LBB 1946/00 (sixzone), with loop-through capability, and universal,
balanced input. One is a 3-pin XLR connector for
microphone or line level (selectable), and the other is a 5pin DIN-connector with all‑call priority contact, which may
also be used to start one of the available chime attention
signals.
The microphone input has a selectable speech filter for
improved intelligibility, a volume control, and bass and
treble tone controls with shelving characteristics
optimized for speech. The call channel is available on the
balanced XLR master output.
The BGM channel provides three inputs on stereo cinchconnectors, converted to mono, with front panel
selection, volume control and bass and treble tone
controls with shelving characteristics optimized for music.
The BGM channel has a direct output on balanced XLR for
dual channel operation. It can also feed the master
output, with the lowest priority, for single channel
operation. Zone selector switches on the front panel
control the BGM routing. An overload protected 24 VDC
output provides power for driving external relays, often
making an external power supply unnecessary.
An emergency/telephone input with signal level detector
(VOX) and volume preset has the highest priority to all
zones. Two trigger inputs (contact closure) activate alarm
or time signals to pre-selected zones. Many different
chime tones are available. A PC audio input with RS-232
control provides software controlled zone configuration,
or automatic messaging in combination with the
LBB 1965/00 Plena Message Manager. There are six levels
of priority available for BGM, microphone, call stations,
trigger inputs and emergency input. A set of relays directs
the amplifier output(s) to different loudspeaker groups
(zone switching).
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2 | LBB 1925/10 Plena System Pre-Amplifier
Each zone has a tri-state control on the front panel that
can turn it off, switch it to the call channel, or to the BGM
channel. The all‑call microphone input and emergency
activation override the call station selection on the call
channel. Each zone has separate priority overrides with
preset volume levels. This assures an appropriate
message volume, independent of any local volume
settings, such as for BGM. Both three‑wire and four‑wire
override schemes are supported. An override also
activates a voltage-free contact (call-active) available for
external control and monitoring. The master output
channel, or one of the input channels, can be monitored
through the headphone connector and/or the
LED VU‑meter.
Controls and indicators
Front
LED power meter
•
Power on LED
•
Call active LED
•
Three knobs for mic/line volume, treble, and bass
•
levels
Three knobs for BGM volume, treble, and bass levels
•
BGM source selection knob
•
Six zone-selections keys
•
Six zone status LEDs
•
On/off switch
•
Back
EMG input volume control
•
Mains voltage switch
•
Interconnections
Front
Headphone jack
•
Back
One (DIN or XLR) Mic/line input
•
Two (DIN/DIN) call station inputs
•
PC audio (cinch) input
•
Priority input
•
Master (XLR) output
•
BGM (XLR) output
•
Emergency signal input
•
Two trigger inputs
•
RS-232 (DE-9)
•
Three (cinch) CD, tape, aux inputs
•
Six 100 V speaker outputs
•
24 VDC output
•
24 VDC input
•
Three control inputs
•
Ground screw
•
IEC mains socket
•
Certifications and Approvals
Region Certification
Europe CE Declaration of Conformity
Safety acc. to EN 60065
Immunity acc. to EN 55103-2
Emission acc. to EN 55103-1
Installation/Configuration Notes
LBB 1925/10 rear view
Parts Included
Quantity Component
1 LBB 1925/10 PLENA System Pre-amplifier
1 Power cord
1 Set of 19”mounting brackets
1 Plena CD
1 Installation and User Instructions
Technical Specifications
Electrical
Mains power supply
Voltage 230/115VAC, ±15%, 50/60 Hz
Current inrush 230/115 VAC, 1.5/3 A
Max power consumption 25 VA
Battery power supply
Voltage 24 VDC, +10% / -15%
Current max 1 A
Performance
Frequency response 50 Hz to 20 kHz (+1 / -3 dB)
Distortion <0.5%
Bass control ±10 dB @ 100 Hz
Treble control ±10 dB @ 10 kHz
Channel separation >70 dB @ 1 kHz
Priority mute >40 dB
Dynamic range 100 dB
Mic/line input 1 x
Connectors 5‑pin DIN, 3‑pin XLR, balanced, with
phantom power
Sensitivity 1 mV (mic), 200 mV (line)
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