Chapter 4: Supplementary applications
82 EST3X Technical Reference Manual
Amplifiers
Amplifiers are designed to feed a single audio zone and provide an integral
24 VDC visual notification appliance circuit. Amplifier modules are available in
20 and 40 watt versions, with each amplifier providing a single supervised Class
B or A audio output circuit. The amplifier is configurable for either 25 or 70 VRMS
output. An independent supervised Class B or Class A, 24 VDC, 3.5 A
notification appliance circuit (NAC) is also provided on the 20 and 40 watt
amplifiers to drive notification appliances. In addition, automatic backup
amplifiers can be added on a switched common backup configuration.
Each audio power amplifier has an integral demultiplexer, making the eight audio
channels available to the amplifier’s input, as directed by the system
programming. Each amplifier also contains circuitry that handles routine signal
processing functions such as channel priority.
The amplifier’s output is a dedicated, supervised, 25 or 70 VRMS speaker circuit,
which covers one audio zone in the protected facility. Figure 14 on page 83 is an
example of an enclosure with two zone amplifiers and a backup amplifier. In
response to an alarm, selected audio amplifiers have been connected to the
required audio channels. Note in the example that two different audio signals are
being broadcast simultaneously.
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