GAI-Tronics PA250-001 User Manual

Pub. 42004-340E

GAI-TRONICS® CORPORATION

A HUBBELL COMPANY

Model PA250-001

250 Watt Central Amplifier

Confidentiality Notice

This manual is provided solely as an operational, installation, and maintenance guide and contains
sensitive business and technical information that is confidential and proprietary to GAI-Tronics.
GAI-Tronics retains all intellectual property and other rights in or to the information contained herein,
and such information may only be used in connection with the operation of your GAI-Tronics product or
system. This manual may not be disclosed in any form, in whole or in part, directly or indirectly, to any
third party.

General Information

Product Overview

The Model PA250-001 250 Watt Central Power Amplifier is designed for use in public address systems.
It can be mounted in standard, commercially available 19-inch racks and cabinets, or placed on a table or
shelf. This manual describes the installation, operation, and maintenance of the amplifier.

System Requirements and Limitations

The Model PA250-001 is designed to be connected to 8-ohm speakers via the direct 8-ohm connection, or
connected to speakers with variable-impedance, line matching transformers designed to match the
amplifier’s line output voltage of 25 V or 70.7 V.

Figure 1. Model PA250-001 Outline – Front View

GAI-Tronics Corporation P.O. Box 1060, Reading, PA 19607-1060 USA

610-777-1374 n 800-492-1212 n Fax: [phone]

VISIT WWW.GAI-TRONICS.COM FOR PRODUCT LITERATURE AND MANUALS

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Features and Functions

• Internal power supply with soft start

• Compact 19-inch rack mountable design (2U {with feet removed})

• Rear-mounted speaker connection terminals for direct 8-ohm bridge output or transformer isolated

outputs for 25 V/70.7 V (CLASS 2) line operation

• Separate rear recessed input level control for 600-ohm and Tel-Page terminals

• Automatic voice-activated Hi-Z input muting (user-defeatable)

• Multiple internal protection circuitry, i.e. output DCV sense, output short circuit, thermal runaway, ac

main circuit breaker, low voltage power supply fuses.

• Rear mounted, grounded ac convenience outlet (unswitched – 2 A max.)

Important Safety Instructions

WARNING

When using this product, these basic safety precautions should always be

followed to reduce the risk of fire, electrical shock, and/or injury to persons:

1. Read these instructions first.

2. Keep these instructions.

3. Heed all warnings.

4. Follow all instructions.

5. Do not use this apparatus near water.

6. Clean only with a dry cloth.

7. Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.

8. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus

(including amplifiers) that produce heat.

9. Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two

blades with one wider than the other one. A grounding-type plug has two blades and a third
grounding prong. The wide blade or the third prong is provided for your safety. If the provided plug
does not fit into your outlet, consult an electrician for replacement of the obsolete outlet.

10. Protect the power cord from being walked on or pinched particularly at plugs, convenience

receptacles, and the point where they exit from the apparatus.

11. Only use attachments/accessories specified by the manufacturer.

12. Use only with the cart, stand, tripod, bracket, or table specified by the manufacturer, or sold with the

apparatus. When a cart is used, use caution when moving the cart/apparatus combination to avoid
injury from tip-over.

13. Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been

damaged in any way, such as power-supply cord or plug is damaged, liquid has been spilled or
objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not
operate normally, or has been dropped.

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Description of Major Components

This assembly includes external components accessible to the user as well as internal components or
subassemblies.

Internal Components

The assembly contains the following major components or subassemblies. Please refer to Figure 2 below:

• Chassis

• AC power input transformer

• Audio line output transformer

• Output power amp/heatsink PCBA

• Audio input PCBA

Figure 2. Component Subassembly Detail – Top view (cover removed)

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External Components

The Model PA250-001 Amplifier’s front panel includes the following components. Refer to Figure 3
below:

• POWER ON switch: controls the main ac power to the amplifier.

• POWER ON LED: illuminates when ac power is applied to the amplifier.

• PEAK LED: illuminates steady at rated power output and flashes during audio peaks that approach

the rated output.

• VOLUME: master output level control of the amplifier.

• CB (circuit breaker): primary ac protection for amplifier that provides a visual indication of a trip

condition.

Figure 3. Model PA250-001 Amplifier – Front View

The amplifier’s rear view includes the following components. Refer to Figure 4 below:

• AC power cord

• AC convenience outlet

• Audio input terminal block connections for Tel-Page and 600-ohm

• Tel-Page/600-ohm input gain control (recessed)

• Dual Hi-Z input connection

• 25V/70V LINE IN/OUT switch

• Audio output terminal block connections for 8 ohm, 25 V or 70 V

2 AMP MAX 120 VAC 60HZ

Figure 4. Model PA250-001 Amplifier – Rear View

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