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Installation Sheet 

27JUN07 

 P/N: 387463 REV: 4.0 

3-ZA20A, 3-ZA20B, 3-ZA40A, 3-ZA40B - Zoned Audio Amplifiers  

1 / 3 

3-ZA20A, 3-ZA20B, 3-ZA40A, 3-ZA40B 

Zoned Audio Amplifiers 

 

Product description 

TB2

TB1

J3

J4

JP1
JP2

1

1

NAC/B

-

+

24VDC

UNUSED

UNUSED

UNUSED

UNUSED

+

-

-

BACK-UP

+

NAC/B

NAC/A

-

-

S

S

+

+

7 0V

rm

s

25V

rm

s

Front view

Rear view

Audio amp

transformer
subassembly

Audio power
module

subassembly

Configuration
jumpers

Output gain

adjust

Configuration

jumper

 

The 20 and 40 watt zoned audio amplifier modules are key 
components in emergency communication systems that 
consist of audible and visible notification appliances. Models 
are available in Class A and Class B versions. See Table 1 for 
a list of model numbers. The amplifiers provide the following: 

• 

20 or 40 watts of power 

• 

Standard output line levels of 25 Vrms or 70 Vrms 

• 

A 1 kHz temporal (3-3-3) tone to use as an evacuation 
signal and a 20 SPM tone to use as an alert signal in the 
event of a failure of networked audio distribution 

Each amplifier is also provided with an independently 
controlled supervised, power limited 24 Vdc NAC circuit. This 
facilitates the addition of visual notification appliances to audio 
notification circuits. 

Each zoned audio amplifier requires one space on the rail 
chassis assembly. 

Table 1: Models 

Number Description 

3-ZA20A 20 

watt 

zoned 

amplifier 

Class A or Class B audio 
Class A or Class B 24 Vdc outputs 

3-ZA20B 20 

watt 

zoned 

amplifier 

Class B audio 
Class B 24 Vdc outputs 

3-ZA40A 40 

watt 

zoned 

amplifier 

Class A or Class B audio 
Class A or Class B 24 Vdc outputs 

3-ZA40B 40 

watt 

zoned 

amplifier 

Class B audio 
Class B 24 Vdc outputs 

 

Specifications 

Space requirements: 1 rail space 
Frequency response: 400 Hz to 4 kHz at ±3 dB 
Harmonic Distortion: < 7% 
Audio circuit 
 

Input: 8-channel, multiplexed digitized audio 

 

Wiring: Class B (Style Y) or Class A (Style Z) 

 

Output: 20 or 40 W at 25 or 70 Vrms 

 

EOL resistor: 15 k

Ω 

(internal on 3-ZA20A/40A) 

24 Vdc NAC circuit: 
 

Wiring: Class B (Style Y) or Class A (Style Z) 

 

Voltage: 24 Vdc nominal 

 

Current: 3.5 A 

 

EOL resistor: 15 k

 (internal on 3-ZA20A/40A) 

 

For special applications, refer to 

EST3 ULI/ULC 

Compatibility Lists

 (P/N 3100427). 

Wiring 
 

Termination: Wiring connects to removable terminal block 

 

Max wire size: 12 AWG (2.5 mm sq) 

Operating environment 
 

Temperature: 32 to 120 °F (0 to 49 °C) 

 

Humidity: 93% RH, noncondensing at 32 °C 

Current ratings 
 

Standby: 62 mA 

 

Alarm:   1.12 A (3-ZA20A/20B) 
  2.48 

(3-ZA40A/40B) 

Installation instructions 

Caution: 

Operating the amplifier at an output greater than that 

required by the speaker may overdrive the speaker circuit and 
result in damage to the equipment  

To install the amplifier: 

1.  Remove all power from the panel. 

2.  Set jumpers JP1 and JP2 on the audio power module 

subassembly for 25 or 70 Vrms, depending on the input 
required by the audio circuit speakers. 

 

 

 

 

 

JP1   

JP2 

 

 

25 Vrms  

2 to 3 

2 to 3 

 

 

70 Vrms  

1 to 2 

1 to 2 

3.  Set the jumper on the audio amp transformer 

subassembly for 25 or 70 Vrms, depending on the input 
required by the audio circuit speakers. 

4.  Slide the module into the required rail/slot position. 

5.  Gently push the module into the connectors to ensure 

good contact. 

6.  Secure the module to the rail by pushing in the top and 

bottom snap rivet fasteners. 

7.  Connect the field wiring. 

Notes 

• 

The gain control pot should be adjusted to the desired 
output levels using a 1KHz signal after installation. Fully 
counter clockwise is maximum gain and fully clockwise is 
minimum gain. 

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