A 4372 • Phase5 Public Address Amplifier 2x125W

Two 125W amplifiers in a single chassis, designed for powering two individual high power zones with different input sources. Ideal for larger installations such as pedestrian precincts, shopping centres, large venues and public infrastructure.

SKU: A 4372 Categories: , , ,

Manufactured in Australia to stringent engineering criteria, the Phase 5 amplifier series exhibit quite remarkable performance and outstanding reliability. Over 2 years in design and development, the evolution of Phase 5 included extensive consultation and input from pro sound contractors and installers across the country. The host of features incorporated commend this amplifier series to the most demanding of pro sound and industrial PA system applications. Redback Phase 5 amplifiers incorporate on demand multi-staged thermally cued fan forced cooling.

The output power stage is thermally monitored enabling automatic operation of a long life computer style cooling fan to “off” or “on” air flow through a specially designed tunnel heatsink. In quiescent or ordinary cycle paging mode the fan is inoperative. Over temperature sensing is employed to shut down the amplifier in extreme over heat conditions, eg extreme over load and /or over drive misuse. Re–start is automatic once normal temperatures are attained. Output peak limiting.

The output voltage is limited to 105V maximum RMS voltage irrespective of load impedance to prevent damage to speaker load. Standard 100V line PA amplifiers can deliver up to 180 volts or more under conditions of high drive and very light loading. This output over voltage can quickly destroy any loudspeakers connected.

Key Features:

  • Robust design incorporating latest Mosfet technology
  • Very Low noise and distortion
  • 100V outputs
  • 240V AC or 24V DC operation
  • Multi stage thermally cued fan cooling
  • Output Peak Limited
  • Thermal Overload protected
  • Signal Presence Indicators
  • Fault Indicators
  • Power Status Indicators
  • Rack Mountable (suits 19 inch racks)



Developed, designed & assembled in Australia.
Since 1976 Redback PA products have been manufactured in Perth, Western Australia by Altronics. With over 40 years experience in the commercial audio industry, we offer consultants, installers and end users reliable products of high build quality with local product support.

Backed by an industry leading 10 Year Manufacturer Warranty.
Our Redback products have a long tried and tested history of bulletproof reliability. Altronics offers a 10 Year Warranty on all Australian Made Redback products. Our local in-house service department has all the know how to answer technical queries and provide timely service.

Power Output: 2 x 125 Watts RMS
Distortion: < 0.5%, @ 1kHz
Output Line: 100V

Frequency Response
Mic Inputs: 50Hz – 12kHz, -3db
Mic Sensitivity (3 pin XLR): 500mV

Signal to noise ratio
Mic Inputs: > 75db below rated output
Line Output: 600Ω balanced, 0dB , 3 Pin XLR

Output Connectors
Speakers: Screw terminals

Output Connectors
Speakers: Screw terminals

Input Connectors
Inputs: 3 pin XLR balanced
24V DC power: Screw terminals
240V AC power: IEC power connector

Mic inputs: Volume
Power: On/off switch
Indicators: Power, signal present, output peak limiting, overtemp, current limit, Protect, Half Power, 24V DC, Mains

Power & Dimensions
Power Supply: 240V AC or 24V DC
Fuse Protection: 7.5A AC , 2x 10A DC
Dimensions: ≈483W x 410D x 88H

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