Audio international PA-7500A Installation Manual
Audio International PA-7500A is a high-performance cabin audio amplifier that delivers excellent frequency response and clear sound quality. It features four channels with 75 watts peak output each, a built-in 135 Hz crossover, and provisions for PA audio override input. The compact and lightweight design with minimal heat generation makes it ideal for aircraft installations. PA-7500A seamlessly integrates with AI's proprietary RS-485 serial data bus, allowing communication with entertainment switch panels. Experience superior in-flight audio with the PA-7500A.
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Installation Manual
PA-7500A
Cabin Audio Amplifier
Document # 540056A
7300 Industry Drive, North Little Rock, AR 72117
Phone: 501-955-2929 Fax: 501-955-2988 www.audiointl.com
Audio International, Inc. PA-7500A Installation
Date
Document Revision History
Description Rev. Level
IR 10/1997
A 7/2000
Document #
520754 Rev A
Reference Documents
Description
PA-7500A Outline Drawing
Service Bulletin List
Service
Bulletin # Revision
Illustration #
2.2
Table of Illustrations
Description
Block Diagram – Typical Application
Date
Page #
5
PROPRIETARY INFORMATION NOTICE: Despite any other copyright notice, this document and information disclosed herein contains confidential, proprietary designs owned by Audio International, Inc.
Neither this document nor the data contained herein shall be reproduced, used, or disclosed to anyone without the written authorization of Audio International, Inc.
Document # 540056A, Rev. A, 7/2000 Page 1 of 11
Audio International, Inc. PA-7500A Installation
Table of Contents
Section Description Page
1.0
2.0
3.0
1.1
1.2
General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Purpose of the Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3
3
3
1.3 Operational Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4 Optional Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2 Block Diagram – Typical Application. . . . . . . . . . . . . . . . . . . . . 4
4.0
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1 Prior to Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2 Unpacking and Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
6
3.4
3.5
3.6
3.7
3.8
Wiring Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Physical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mating Connector Information . . . . . . . . . . . . . . . . . . . . . . . . .
Pinout Assignments and Descriptions . . . . . . . . . . . . . . . . . .
6
7
7
8
8
3.9 Post-Installation Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.1 General Troubleshooting Procedures . . . . . . . . . . . . . . . . . . . . 10
4.2 Troubleshooting Chart . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . 10
5.0 10
6.0 Reference Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
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Audio International, Inc. PA-7500A Installation
PA-7500A
Cabin Audio Amplifier
1.0 General Information
1.1 Introduction
This manual contains information for the proper installation of the Audio
International, Inc. (AI) Cabin Audio Amplifier, Model No: PA-7500A. Also included are physical and electrical characteristics of the unit.
1.2 Purpose of the Equipment
The PA-7500A is a class ‘D’, 300 watt, dual stereo power amplifier that takes low audio signal and magnifies it. This audio amplifier delivers high performance, excellent frequency response, and clear sound quality. The unit has a small footprint and generates little heat yet produces dual output, high-powered, high fidelity sound.
The unit has four (4) channel outputs, 75 watts peak output per channel.
A 135 Hz crossover is incorporated within the unit. Provisions are included for PA audio override input. The unit is designed to interface with AI’s proprietary RS-485 serial data bus allowing the entertainment switch panels to communicate with the audio amplifier.
1.3 Operational Features
Listed below are key features of the PA-7500A: q q
Solid state circuitry
Small footprint q q
Minimal heat generation
Dual output, high-power, high fidelity sound q q q
Four (4) channel outputs, 75 watts peak output per channel
Electric crossover – 135 Hz range
PA override input q Automatic speaker turn ‘ON’ and PA audio level setting when PA interface is activated q q
Lightweight, compact
Specially designed to meet aircraft standards
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Audio International, Inc. PA-7500A Installation
1.4 Optional Equipment
Audio International, Inc. offers a complete line of speaker systems to enhance any aircraft entertainment system. Contact your AI representative for details.
2.0 Application
2.1 Introduction
The PA-7500A will produce stereo audio output for the entertainment system and monaural audio for page / chime. Each amplifier is designed to interface with AI’s proprietary RS-485 serial data bus allowing all entertainment switch panels to communicate with the audio amplifier.
The unit has the capability of producing four (4) channels, 75 watts RMS peak output. Output impedance 4-ohms per channel; input impedance
10-k briefer, 1 VRMS nominal. Emergency input power is provided for PA override capabilities. Electric crossover low range 20 – 135 Hz, high range 135Hz – 20 kHz.
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Audio International, Inc. PA-7500A Installation
3.0 Installation
3.1 Prior to Installation
3.1.1 During the design and layout of the aircraft cabin, careful consideration of the location of this module is necessary. Some of the items to be considered include:
•
Space
•
Available power supply
•
Environmental conditions (temperature, humidity, etc.)
•
Length of cable runs
3.1.2 The PA-7500A shall be installed to conform to the standards designated by the customer, installing agency, and existing conditions as to the unit location and type of installation.
3.1.3 Mounting screws are required to secure the unit. Refer to
Section 6.0, Reference Drawings, for mounting hole diameters and configuration.
3.1.4 The unit must be located as close to source equipment as possible.
Long low-level runs may introduce noise into the audio signal.
3.2 Unpacking and Inspection
Carefully open the packaging and remove the unit. Verify that all components have been included in the package per the packing list.
Inspect the unit for damage. Retain the packing materials and packing list.
If damage has occurred during shipping, a claim must be filed with AI within 24 hours and a “Return Request Authorization Number” must be obtained from AI. Refer to the front cover of this manual for address and telephone number of Audio International. Repackage the unit in its original packaging materials and return it to AI following instructions given by the AI representative. If no return is necessary, retain the packing materials for storage or reshipment if necessary.
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Audio International, Inc. PA-7500A Installation
3.3 Cautions and Warnings
3.3.1 It is important to do a pin-to-pin power and ground check on all connectors. Ensure that power and ground are applied only where specified. Damage to the unit may result if power or ground is applied to the wrong points.
3.3.2 DO NOT connect or disconnect the module while power is applied.
3.3.3 DO NOT remove any factory-installed screws. Damage to the units may result and void any warranties.
3.3.4 ESD (Electro Static Discharge) guidelines shall be followed.
3.4.1 Introduction
The installing agency must supply and fabricate all external cables and mating connectors. The length and routing of external cables must be carefully studied and planned before attempting installation of the equipment. Allow adequate space for installation of cable and connectors. Avoid sharp bends and placing cables near aircraft control cables. Maintain a MINIMUM clearance of three (3) inches from any control cable. If wiring is run parallel to combustible fluid or oxygen lines, maintain a separation of six (6) inches between the lines.
All power and ground wires shall be 18 AWG, MINIMUM. Power ground wires shall be grounded within twelve inches of the unit. All wires shall be in accordance with MIL-W-22759 or equivalent.
Protect power wires with circuit breakers or fuses located close to the electrical power source bus.
All audio input and output cables shall be 20 AWG, MINIMUM (16 to 18 preferred). All audio lines require twisted, shielded cable with the cable shields grounded at the source. Twisted shielded cable must be in accordance with MIL-DTL-27500 or equivalent.
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Audio International, Inc. PA-7500A Installation
.
3.4.4 AI Proprietary RS-485 Data Bus
The PA-7500A is designed to interface with other AI equipment via
AI’s proprietary RS-485 serial data bus. This is a bi-directional data bus that allows multiple units to be connected simultaneously.
The data bus is to be implemented using a twisted shielded pair cable in accordance with MIL-DTL-27500 or equivalent. The wire size for the conductors in this cable is to be 22 AWG , MINIMUM.
The shield is to be connected wherever a shield pin is provided.
Shield terminations are to be made as close to the connector pin as possible. In the event shield pins are not provided, the data bus shield must be terminated per AI’s proprietary RS-485 specification.
All modules on AI’s proprietary RS-485 data bus shall be connected in a “daisy-chain” configuration. AI’s proprietary RS-485 serial data bus specification is available upon request.
3.5 Physical Characteristics
3.5.1 Refer to Section 5.0 for unit dimensions.
3.5.2 Refer to Section 6.0 for attachment points.
3.5.3 When mounting the unit, allow sufficient space for mating connectors.
3.6 Electrical Characteristics
3.6.1 Refer to Section 5.0 for electrical specifications.
3.6.2 P1 is a 25-pin connector. The signals interfaced through P1 are left
/ right speaker, +28 VDC emergency power and woofer outputs.
Power requirement is +28 VDC at continuous power output at 12 amps (15 amp breaker – 4 channel). Emergency power input is provided for cabin page and chime functions in case of power failure.
3.6.3 P2 is a 37-pin connector. The signals interfaced through P2 are PA
/ chime, briefer, stereo left and right (high and low), data bus control, and +28 VDC power. When the briefer key input is activated, all entertainment audio will be muted. The PA key input has the highest priority and will override all briefer and entertainment audio inputs. When the PA source is keyed, all other audio will be muted. Chime inputs will operate simultaneously with the briefer.
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Audio International, Inc. PA-7500A Installation
3.7 Mating Connector Information
All wiring harnesses to the unit are supplied and fabricated by the installing agency. P1 mating connector is SD25F10HVL0. P2 mating connector is SD27F10HVL0.
Assignment Descriptions
P1 P2
Pin #
1
2
3
4
6
7
8
Description
Left Speaker 1 – High
Left Speaker 2 – High
Left Speaker 1 – Low
Left Speaker 2 – Low
+ 28 VDC
+ 28 VDC
+ 28 VDC
10 Right Speaker 1 – Low
11 Right Speaker 2 – Low
12 Right Speaker 1 – High
13 Right Speaker 2 – High
15 Emergency Bus +28 VDC In
16 + 28 VDC
17 + 28 VDC
18 Ground
19 Ground
20 Ground
21 Ground
23 Ground
24 Ground
Pin #
1
2
3
4
5
6
No Connection
PA MIC +
Wgt-On-Wheels Input (Ground)
Briefer +
No Connection
Left In +
Description
7
8
Left In -
Right In +
9 Right In -
10 Data Bus Shield
11 +28 VDC (Adj)
12 Data Bus Ground (Adj)
13 Data Bus SER + (Adj)
14 Data Bus SER – (Adj)
15 No Connection
16 No Connection
17 No Connection
18 No
19 No
20 PA -
21 No
22 Briefer
23 No
24 PA Key
25 Briefer Key
26 + PA Output
27 - PA Output
28 PA Key Out
29 Data Bus SER Data +
30 Data Bus SER Data -
31 Chime In (+28 VDC)
32 TT Chime In (+28 VDC)
33 Call In (GND)
34 Hook In (GND)
35 PA Sidetone +
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Audio International, Inc. PA-7500A Installation
3.9.1 With aircraft power ‘ON’, test the cabin audio amplifier. Any unit providing audio that is connected to the RS-485 data bus may be used to test proper operation the unit.
3.9.2 While an audio unit is sending audio signals through the amplifier, key and speak into a microphone to ensure that the page / chime overrides the entertainment audio. Ensure all microphones are tested. Verify that the briefer audio can be heard through the speakers.
3.9.3 Verify that the selected material may be heard through the headphone and/or speaker system. Activate the PA key. Verify PA overrides the headphone and/or speaker system.
3.9.4 Remove power from the amplifier and verify that the +28 VDC emergency power is supplied to the amplifier. Verify that the subwoofers are disabled while emergency power is applied.
Ensure that PA audio can be heard in the speaker system from all respective microphones.
3.9.5 Audio level adjustments are accomplished via AI’s proprietary
RS-485 data bus. Contact Audio International, Inc. for setup requirements.
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Audio International, Inc. PA-7500A Installation
4.0 Troubleshooting Guide
4.1 General Troubleshooting Procedures
Many problems can be isolated with the following general techniques:
•
To verify power to the unit, recheck +28 VDC power is applied to the proper pins on the unit. Use a voltmeter to verify correct level.
•
Reset by removing power from the unit for at least one (1) minute and reapply power. Verify the problem still exists.
•
Recheck all connections to the unit for security. Check all harness runs for possible pinching. Recheck all pinouts for application accuracy.
4.2 Troubleshooting Chart
No sound Unit improperly installed
No audio material in source unit
Solution
Verify +28 VDC power and audio input is present
Insert audio material in source unit
Contact AI quality adjusted properly
5.0 Specifications
Physical Specifications
Housing
Dimensions
(l x w x h)
Weight
Aluminum
9.3" x 4.9" x 2.0"
23.62cm x 12.45cm x 5.0cm
2.7 lb / 1.22 kg
Electrical Specifications
Power
Emergency Power
Data Bus Type
Electric Crossover
Channel Output Power
Input Impedance
Output Impedance
+ 28 VDC at continuous power output
@ 12 amps,
3.5 amps MINIMUM, 17.5 amps MAXIMUM
+ 28 VDC Page / Chime
AI Proprietary RS-485
Low Range: 20 Hz to 135 kHz
High Range: 135 Hz to 20 kHz
4-Channel, 75 watts peak output
10-k briefer, 1 VRMS (NOMINAL)
4-ohms per channel
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Audio International, Inc. PA-7500A Installation
The following diagrams show the unit dimensions and connector locations for the
PA-7500A. All dimensions are shown in inches.
Document # 540056A, Rev. A, 7/2000 Page 11 of 11

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