Redback Phase4 Public Address (PA) 2x125W Amplifier

$1,365.00 including GST

Redback A4072B 100v Line Amplifier

3 in stock (can be backordered)

SKU: A4072B Category: Tags: , , , ,


Manufactured in Australia to stringent engineering criteria, the Phase 4 amplifier series exhibit quite remarkable performance and outstanding reliability. Over 2 years in design and development, the evolution of Phase 4 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 4 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”, “low” or “high” 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. Reā€“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.


  • 2 X 125W amplifiers in a single chassis
  • Multi-stage thermally cued cooling
  • LED bargraph VU meter
  • Input signal presence indicator
  • Output peak limited
  • 2U 19″ rack mount
  • 3 pin XLR input, 3 pin XLR loop out
  • Level control rear mounted
  • 100V, 70V and 4 – 16 Ohm outputs
  • Thermal and overload protection
  • 240V AC, or 24V DC operation
  • 300mA 24V battery trickle charge

Specifications :

  • Power Output: 2 x 125 Watts RMS
  • Distortion: < 0.5%, @ 1kHz
  • Frequency Response: 50Hz – 15kHz, -3dB
  • Speaker Outputs: 100V, 70V, or 4 – 16 Ohm
  • Sensitivity: 500mV balanced
  • Signal to Noise Ratio:(Peak Limiting By-Passed) > 90 dB
  • Line Output: 600 Ohm balanced, 0dBV
  • Speakers: Screw Terminals
  • Line Out: 3 pin XLR
  • Trickle Charge: Screw Terminals
  • Inputs: 3 pin XLR balanced
  • 24V DC Power: Screw Terminals
  • 240V AC Power: IEC Chassis Socket
  • Master: Volume (on rear panel)
  • Power: On/Off Switch
  • Indicators: Power, Fault, VU Meter, Signal Present, Output Peak Limiting
  • Power Supply: 240V AC or 24V DC (nominal)
  • Protection: 7.5A AC Fuse and 2 x 10A DC Fuses
  • Dimensions: 483W x 407D (Including Handles) x 88H
  • Weight: 18kg

Additional information

Weight 18 kg
Dimensions 50 × 42 × 12 cm


There are no reviews yet.

Only logged in customers who have purchased this product may leave a review.