Public Address (PA) Mixer Amplifier 250W 100V 4 Zone A4280

SKU: 9321758232583


This Redback 4 Zone 250 Watt 100V Public Address Mixer Amplifier is similar in functionality to the A 4377/A4387 amplifiers with the addition of four 100V line output zones. During normal use, you are able to select via the front panel switches, any zone on or off to control BGM programming. Remote paging to each zone is made possible by connecting the A 4660 paging console to the amplifier via Cat6 cable (2 consoles @ max 300m). This allows for paging to selected zones or all call, muting BGM to all zones. At the completion of the announcement, music will be restored to previously selected zones. BGM can also be selected on or off to all zones remotely from the paging console. When using the paging console, these microphones assume priority between input 1 and input 2 on the amplifier. If two consoles are connected, they operate on a first in, first served basis, activating a system busy indicator on the inoperative console.


  • Multi-stage thermally cued fan cooling
  • 2U 19” rack mount (with optional A 4376)
  • Tape record out terminals
  • Provision for connection to Redback A4660 touchscreen paging console
  • MP3 based Alert/Evac tones with MP3 voice over message for emergency tones (built in)
  • 3 mic input and 4 auxiliary inputs
  • Phantom powering available on all inputs
  • Adjustable vox muting on inputs 1 & 2.
  • Bass and treble tone controls
  • Terminals for 100V line output
  • 240V AC or 24V DC power operation
  • Thermal & fuse overload protection
  • Built in short circuit protection
  • Australian designed & assembled


Output Wiring Conversion


  • Power output: 250W
  • Distortion: <0.5% @ 1kHz
  • Output line: 100V
  • Frequency response: 50Hz - 12kHz, -3dB
  • Line inputs: 300mV
  • Mic line sensitivity: 3mV balanced
  • Mic input: >75dB below rated output
  • Line inputs: >81dB below rated output
  • Speaker connection: Pluggable terminals
  • Power connection: IEC or 24VDC pluggable terminal
  • Audio inputs: 3 pin XLR, stereo RCA, 3.5mm jack
  • Controls: Volume (3), Bass, Treble, Master, Zone Selection (4)
  • Bass adjustment: ±10dB @ 100hz
  • Treble adjustment: ±10dB @ 10kHz
  • Indicators: Power, 24VDC, Fault, Peak Limit, Over Load, Paging Active
  • Fuse protection: 7.5A AC, 10A DC
  • Power: 240V AC or 24V DC (nominal)
  • Dimensions: 483 x 270 x 88mm

100% developed, designed & assembled in Australia.
Since 1976 Redback PA products have been manufactured in Perth, Western Australia by Altronics. With over 45 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. 

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