Bosch LBB 1906/10 User Manual

Communications Systems | LBB 190x/10 and LBB 191x/10 Plena Mixer Amplifiers
The Plena mixer amplifier is a versatile, high-performance
unit with four mono microphone inputs and a music input.
It fulfills a wide variety of public address requirements at
a surprisingly low cost.
Functions
All input channels have a phantom power supply to
provide power to condenser microphones and selectable
speech filters for improved intelligibility. Input channels 3
and 4 can also be switched to line sensitivity. Separate
music inputs are available with their own input selector
and volume control.
Input channel 1 can take priority over all other
microphone and music inputs. Contact closure on the 5-
pin DIN connector, or if the signal level on channel 1
exceeds a predefined value (VOX) will activate priority. A
2-tone chime can be configured to precede a priority
announcement. A telephone or emergency input with VOX
activation and its own preset volume control overrides all
other input.
Loop through input and output connections enable
external sound processing equipment, such as an
equalizer or the Plena feedback suppressor, to be
connected between the preamplifier and the power
amplifier stages. An LED VU-meter monitors the master
output. The unit also has a tape output channel.
The Plena mixer amplifiers come in a range of maximum
output power. This power is directly available on 70 V and
100 V constant voltage connections and on a low
impedance connection for an 8 ohm load. Moreover, the
amplifiers have a separate 70 V / 100 V call-only output
channel for addressing areas where only priority
announcements are required, and a 70 V / 100 V mix-only
output channel for areas where no priority
announcements should be heard. The call-only output can
also be used for 3-wire remote, volume control override.
For more output power than the built-in power stage can
deliver, additional Plena power amplifiers can be
connected to the balanced line output in a loop-through
arrangement.
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 when certain announcements or background music
should not be heard in part of a building. Priority calls,
however, are always routed to both zones.
LBB 190x/10 and LBB 191x/10 Plena
Mixer Amplifiers
▶
Range of single and dual zone mixer amplifiers from
30 W to 120 W
▶
Four low-noise balanced inputs for microphone or line
▶
Selectable priority & VOX switching on microphone
input 1
▶
Optional 2-tone chime to precede announcements
▶
VOX activated emergency override
▶
Outputs for normal, call-only and mix-only zones
▶
Choice of CD, tuner or auxiliary music inputs
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Bosch LBB 1906/10 Specifications

General

S/N (flat at max. volume)	> 70 dB
Mains Voltage	50/60 Hz
Battery Voltage	24 VDC
Inputs	6
Microphone Input	-40 dBV
Gain	Adjustable
Outputs	Loudspeaker, Line, Headphones
Loudspeaker outputs	2 x 10 W / 4 Ω
Line Output	0 dBV
Mounting	19" rack mount (1U)
Operating temperature	+45°C (113°F)
Storage temperature	-40 ºC to +70 ºC (-40 ºF to +158 ºF)
Output Impedance	4 Ω

Summary

Key Functions and Features

Controls and Indicators

Front Panel Controls and Indicators

Lists front panel controls and indicators such as power, volume, and source selection.

Rear Panel Controls and Connections

Details rear panel controls, switches, and various input/output connections.

Certifications and Approvals

Lists the safety and compliance certifications obtained by the product.

Included Parts and Accessories

Technical Specifications Overview

Product Ordering Information

Important Safety Safeguards

About This Manual

General Safety Precautions

Internal Settings and Adjustments

Configuring VOX for Microphone Input 1

Explains how to configure the voice-controlled priority (VOX) feature for input 1.

Setting Speech Filters for Intelligibility

Describes how to activate speech filters to improve intelligibility by cutting low frequencies.

Adjusting Chime Volume

Explains how to adjust the chime volume for priority calls.

Setting Output Voltage for LBB1903/1906/1912

Details jumper settings for output voltages on specific models.

Setting Output Voltage for LBB1914

Details jumper settings for output voltages on the LBB1914 model.

Rack Installation Guide

External Settings and Connections

Connecting DC Power Supply (Battery)

Explains how to connect a backup power supply using the 24 Vdc input.

Priority Microphone Setup and Connection

Details the connection and functionality of priority microphones.

Chime ON/OFF Switch Functionality

Describes the function of the chime ON/OFF switch and its relation to microphone input 1.

Microphone Input Configurations

Explains how to connect and configure different types of microphones.

Emergency Input Details and Priority

Details the emergency input, its high priority, and volume control settings.

Music Source Input Connections

Guides on connecting CD players, tuners, or tape recorders for background music.

Connecting the Line Output

Explains how to connect the amplifier's line output to other PA amplifiers.

Connecting Loudspeakers

Provides instructions for connecting various types of loudspeakers.

Connecting Constant Voltage Loudspeakers

Details connecting 70 V or 100 V constant voltage loudspeakers.

Connecting Low Impedance Loudspeakers

Details connecting 8 Ohm low impedance loudspeakers.

Mains Power Connection

Mixer Amplifier Operation

Source Selection Guide

Describes how to choose between connected music sources using the selector knob.

Volume and Tone Control Adjustment

Details how to adjust master volume, bass, and treble controls for optimal sound.

Zone Selection (LBB1914/10 Only)

Explains how to use zone buttons to route audio output on the LBB1914/10 model.

Detailed Technical Data

Electrical Specifications

Lists electrical specifications like mains voltage, power consumption, and battery supply.

Performance Metrics

Details performance metrics such as frequency response, distortion, and tone control ranges.

Input Specifications

Specifies technical details for various input types like microphone, music, and emergency.

Output Specifications

Lists technical specifications for master output, tape output, and loudspeaker outputs.

Environmental Conditions

Specifies operating and storage temperature ranges, and humidity levels.

General Technical Data

Provides general technical information including EMC, noise level, dimensions, and weight.