Redback Phase5 40, 60 & 100 Watt 100V Public Address Amplifiers


A 4037

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Meet the needs of medium-sized professional public address installations with the Redback 40W, 60W & 100W RMS Public Address (PA) Amplifier. Designed for versatility and reliability, this amplifier is perfect for schools, public halls, workshops, and sporting complexes. It delivers 40W, 60W & 100W RMS output power with a frequency response from 60Hz to 15kHz and a total harmonic distortion (THD) of less than 0.5%.




  • VOX Muting: Input 1 (mic or line) mutes inputs 2-3, and input 2 (mic or line) mutes input 3.
  • Three Balanced Microphone Inputs: With phantom power for clear and consistent audio quality.
  • Three Line RCA Inputs: For connecting various audio sources.
  • Bass and Treble Controls: Customize the sound to suit your environment.
  • 100V Line Output: Ideal for long-distance audio distribution.
  • Flexible Power Options: Operates on 240V AC mains or 24V DC for battery backup during power failures.
  • Short Circuit Protection: Built-in thermal overload shutdown to safeguard the amplifier.
  • 19” Rack Mount Kit Included: Easy integration into professional audio setups.
  • Tape Output RCA Sockets: For recording or connecting additional equipment.
  • Optional Add-ons:

A 4573 Alert/Evac Option Board: Generates pre-chime, bell, alert, and evacuation tones with adjustable delay.

A 4373 Digital Remote Volume Option Board: Allows remote volume adjustment via A 2280B wall plate.

  • Australian Designed & Assembled: Quality craftsmanship you can trust.




  • Power Output:
    • 40 watts RMS (A4037)
    • 60 watts RMS (A4043)
    • 100 watts RMS (A4047)
  • Distortion: < 0.5% @ 1kHz
  • Signal to Noise Ratio: Typically 75dB below rated output. All inputs
  • Mic inputs: 50Hz - 10kHz, -3dB
  • Line inputs: 60Hz - 15kHz, -3dB
  • Output line: 100V
  • Mic 1-3: 3mV
  • Line inputs 1-3: 300mV
  • Speakers: Screw terminals
  • Current Draw:
    • 220mA Standby, 3A Full @ 24V DC (40w A4037)
    • 220mA Standby, 4.5A Full @ 24V DC (60w A4043)
    • 220mA Standby, 7A Full @ 24V DC (100w A4047)
  • Protection:
    • 1A AC fuse and 4A DC fuse (40w A4037)
    • 2A AC fuse and 5A DC fuse (60w A4043)
    • 4A AC fuse and 8A DC fuse (100w A4047)
  • Weight:
    • 7.1kg (40w A4037)
    • 7.4kg (60w A4043)
    • 9kg (100w A4047)
  • Dimensions: 423W x 225D x 88H mm


Input Connectors

  • Mic 1-3: 3 pin XLR balanced
  • Line inputs 1-3: RCA stereo socket
  • 24V DC power: Screw terminals
  • 240V AC power: IEC power connector
  • VOX Muting: 60dB below rated output
  • Remote volume: Screw terminals



  • Mic inputs: Volume
  • Line inputs: Volume
  • Bass: ±10dB @ 100Hz
  • Treble: ±13dB @ 10kHz
  • Power: On/off switch
  • Indicators: Power, Overload
  • Power supply: 240V AC or 24V DC


*Specifications are subject to change without notice.

Redback Phase5 40, 60 & 100 Watt 100V Public Address Amplifiers

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Australian owned since 1980


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