Bosch LBB19XX User Manual

Communication Systems | LBB 19xx/10 Plena Mixer Amplifiers

LBB 19xx/10 Plena Mixer Amplifiers

Range of single and dual zone mixer amplifiers from

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30 W to 120 W
Four low-noise balanced inputs for microphone or

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line
Selectable priority & vox switching on microphone

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input 1
Optional 2-tone chime to precede announcements

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Separate overruling emergency input with vox

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Loudspeaker connections for normal, call-only and

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mix-only zones
Choice of CD, tuner or auxiliary music inputs

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The Plena mixer amplifier is a high-performance,
versatile four-microphone inputs mono mixer amplifier,
capable of fulfilling a wide variety of public address
requirements at surprisingly low cost.

Functions

All microphone inputs have a phantom power supply to
provide power to condenser microphones and
selectable speech filters for improved intelligibility.
Microphone inputs 3 and 4 can also be switched to line
sensitivity. Furthermore, separate music inputs are
available with their own input selector and volume
control.
Microphone input 1 can be given priority over all other
microphone and music inputs. Priority is given upon
contact closure on the 5-pin DIN connector or if the
signal level on input 1 exceeds a predefined value (VOX).
A 2-tone chime can be selected to precede a priority
announcement.
A telephone or emergency input with VOX activation is
provided that takes overall priority, and has its own
preset volume control.
An interconnection input and output enables external
sound processing equipment to be connected, such as
an equalizer or the Plena feedback suppressor between
the preamplifier section and the power amplifier. A tape

output is provided and a LED VU-meter allows the
master output to be monitored.
The Plena mixer amplifiers come in a range of output
powers. This power is directly available on 70 V and 100
V constant voltage outputs and on a low impedance
output for 8 ohm load. Moreover, the amplifiers have a
separate 70 V / 100 V Call Only output for addressing
areas where only priority announcements are required,
and a 70 V / 100 V Mix Only output for areas where no
priority announcements should be heard. The Call Only
output can also be used for 3-wire remote volume
control override.
Additional Plena power amplifiers can be connected in
a loop-through arrangement to the balanced line output
if more output power is needed than the built-in power
stage can deliver.
The LBB 1914/10 offers the same functionality as the
LBB 1912/10 but also has two front-panel switches to
direct the amplifier output to two separate zones. This
is useful if some announcements or background music
should only be heard in part of a building. Priority calls,
however, are always routed to both zones, even if
unselected for e.g. music.

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2 | LBB 19xx/10 Plena Mixer Amplifiers

Certifications and Approvals

EMC emission acc. to EN 55103-1
EMC immunity acc. to EN 55103-2

Parts Included

Quantity Components
1 LBB 19xx Plena Mixer Amplifier
1 Power cord

Technical Specifications

Electrical

Mains Voltage 115 Vac/230 VAC,

±10%, 50/60 Hz
Max mains power consumption
LBB 1903/10 100 VA
LBB 1906/10 200 VA
LBB 1912/10, LBB 1914/10 400 VA
Max mains inrush current
LBB 1903/10 4.5 A/9 A (230 Vac/115 VAC)
LBB 1906/10 5 A/10 A (230 Vac/115 VAC)
LBB 1912/10, LBB 1914/10 8 A/16 A (230 Vac/115 VAC)
Battery Voltage 24 VDC, +20%/-10%
Max battery current
LBB 1903/10 1.6 A
LBB 1906/10 3 A
LBB 1912/10, LBB 1914/10 6 A
Performance
Frequency Response 50 Hz – 20 kHz (+1/-3 dB,

@ -10 dB ref. rated output)
Distortion <1% @ rated output power,

1 kHz
Bass Control -8/+8 dB @ 100 Hz
Treble Control -8/+8 dB @ 10 kHz
Inputs
Input 1 (5-pin DIN, balanced with phantom power, 6.3 mm phone jack)
Input 2 (3-pin XLR, balanced with phantom power, 6.3 mm phone jack)
Sensitivity 1 mV
Impedance >1 kOhm
S/N (flat at max volume) 63 dB
S/N (flat at min volume/muted) > 75 dB
CMRR > 40 dB (50Hz-20kHz)
Headroom > 25 dB
Speech Filter -3 dB @ 315 Hz, high-pass,

6 dB/oct
Phantom Power Supply 16 V via 1.2 kOhm
VOX (input 1 only) attack time 150 ms

release time 2 s
Input 3,4 (3-pin XLR, balanced with phantom power, 6.3 mm phone jack)
Sensitivity 1 mV (microphone), 200 mV (line)
Impedance >1 kOhm (microphone), >5 kOhm

(line)
Dynamic Range 100 dB
S/N (flat at max volume) >63 dB (microphone), >70 dB (line)
S/N (flat at min volume/muted) >75 dB
CMRR >40 dB (50 Hz-20 kHz)
Headroom >25 dB
Speech Filter -3 dB @ 315 Hz, high-pass, 6dB/oct