Communications Systems | PRS‑xBxxx Basic Amplifiers
PRS‑xBxxx Basic Amplifiers
www.boschsecurity.com
u High efficiency class-D amplifier channel(s)
u Switched mode power supply
u Local audio inputs
The basic amplifiers are cost effective alternatives to
the regular Praesideo power amplifiers, for situations
where no built-in digital signal processing functions,
such as equalizers, delay and AVC are required. They
do not have a Praesideo network connection. Instead,
these amplifiers are connected to the Praesideo
network via the PRS-16MCI Multi Channel Interface,
which provides the basic amplifier with audio signals
and has full control. There are four versions, the
PRS‑1B500 (1 x 500 W), PRS‑2B250 (2 x 250 W),
PRS‑4B125 (4 x 125 W) and the PRS‑8B060
(8 x 60 W).
The basic amplifiers are completely supervised and
fault events are reported via the multi channel
interface to the Praesideo network controller.
The basic amplifiers provide connections for separate
group A and group B loudspeakers for each zone, and
support class‑A loudspeaker loop wiring. The units
should be mounted in a 19"-rack with the included
mounting brackets.
u Mains and battery operation
u Complete supervision
Notice
Region specific versions of these amplifiers are
indicated by a suffix to the typenumber (-EU, -
CN, ...). The amplifiers are completely identical,
but may differ in certifications, power cord and
country of origin.
Functions
Amplification
The PRS‑1B500 is a single channel, 500 W unit, the
PRS‑2B250 is a two-channel amplifier with 250 W per
channel, the PRS‑4B125 is a four‑channel amplifier
with 125 W per channel and the PRS‑8B060 is an
eight‑channel amplifier with 60 W per channel. The
power supply is switched mode with low inrush
current and the units can run on 48 V, battery stand-by
power.
Connection
The amplifiers have built-in output transformers for
driving 70 and 100 V loudspeakers. They have separate
overload-protected group A and group B loudspeaker
connections, which support class-A loop wiring. The
separate A and B groups of each channel can be
2 | PRS‑xBxxx Basic Amplifiers
configured for redundancy. The units connect to the
PRS-16MCI Multi Channel Interface for audio, control
and supervision, but stand-alone operation is possible.
Audio
The amplifiers have analog audio line inputs for low
priority local audio. Networked audio from the multi
channel interface overrides the local audio.
Security
The units operate both on mains power and on a 48 V
battery power supply for emergency back up, with
automatic switchover. They supervise both of the
power supplies, as well as themselves. They can
optionally monitor loudspeakers and their lines, when
used together with the PRS-16MCI Multi Channel
Interface. Complete channel separation allows one
channel of the amplifier to function as a spare
amplifier for the other amplifier channel.
The amplifier has overload and short circuit
protection. An overheat protection circuit switches off
the power stage and activates the fault LED on the
front panel if the internal temperature reaches a
critical limit.
Controls and indicators
Front
• Two two-color LEDs for mains and battery status
• Four amplifier status/level LEDs (per channel)
Back
• Mains on/off switch
• Mains voltage selector
• Rotary volume control for local audio inputs (per
channel)
Inside
• 70 V / 100 V selection (per channel)
Interconnection
Back
• Mains socket
• Battery backup input
• Two loudspeaker output screw terminals (per
channel)
• Spare amplifier input screw terminal (per channel)
• Two RJ45 connectors (per channel)
• Local audio input screw terminal (per channel)
Certifications and approvals
Safety acc. to IEC 60065 / EN 60065
Immunity acc. to EN 55103‑2 / EN 50130‑4 /
EN 50121‑4
Emissions acc. to EN 55103-1 / FCC-47 part 15B
Emergency acc. to EN 60849 / EN 54‑16 /
ISO 7240‑16
Maritime acc. to IEC 60945
Region Certification
Europe CE
CE DOP
CPD
GL
Parts included
Quantity Component
1 PRS-1B500 Basic Amplifier 1x500 W
or
PRS-2B250 Basic Amplifier 2x250 W
or
PRS‑4B125 Basic Amplifier 4x125 W
or
PRS‑8B060 Basic Amplifier 8x60 W
2/4/8/16CAT 5‑cables (for PRS‑1B500 / PRS‑2B250 /
PRS‑4B125 / PRS‑8B060)
1 Power cord
1 Set of mounting brackets (large) for 19” rack
1 Set connectors
Technical specifications
Electrical
Mains power supply
Voltage 115/230 VAC ±10%, 50/60 Hz
Power consumption Pmax -3 dB* / idle** / standby
PRS-1B500 450 / 52 / 17 W
PRS-2B250 378 / 46 / 18 W
PRS‑4B125 395 / 62 / 16 W
PRS‑8B060 400 / 80 / 16 W
* Alarm tone level
** With pilot tone 15 V
Battery power supply
Voltage 48 VDC -10% to +20%
Power consumption Pmax -3 dB* / idle** / standby
PRS-1B500 365 / 34 / 6 W
PRS-2B250 370 / 38 / 6 W
PRS‑4B125 375 / 48 / 9 W
PRS‑8B060 385 / 62 / 10 W
* Alarm tone level
** With pilot tone 15 V
Performance
Frequency response 60 Hz to 19 kHz (-3 dB)