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QX-280 Series Corporate Power amplifiers


Made in Australia

Like all Quest products, the QX-280 Series is made to survive in a tough world.

Australian QC and advanced design engineering mean years of trouble free service in professional applications.

The QX-280 Series provides a price/performance ratio thatis hard to beat.


Studio quality sound and plenty of channels - the QX-280 Series is available in a wide range of single and multi-channel configurations.

Specifically designed for AV installations and high endcommercial sound, where hi-fidelity audio is required.

Powered with the latest in high quality, energy efficient, Class D amplifiers;

the QX-280 Series amplifiers can be integrated into both low impedance, and 70/100V line installations without compromise

A Closer Look

The QX-280 range consists of three separate models.

  • QX1280 - single channel x 280 Watt
  • QX2280 - two channels x 280 watts
  • QX4280 - four channel x 280 watts

Audio quality is studio class in both high and low impedance operation.

High quality class D amplifier technology makes it possible to have a compact single rack format with the right combination of power and channel density.

The transformerless outputs deliver full range audio toall impedance loads from 4Ω to 70/100V systems.

Each amplifier channel has a selectable 80 Hz high-pass filter (selectable via a swith located on the rearpanel), and a volume control for each channel that can be accessed directly from the front panel.

Each amplifier channel is also provided with a thermally controlled cooling fan.


  • High Efficiency Class-D Amplifier(s)
  • 70/100V or Low Impedance Operation
  • Compact 1RU Chassis
  • Auto-Sleep Function
  • Selectable 80Hz High Pass Filter
  • Built-In Limiter Circuit
  • Thermally Controlled Fans
  • AC power range 85-265VAC 50/60Hz.
  • ErP (1275/2008/EC) compliant standby consumption < 0.5W (*per channel)
  • Available in 1, 2 or 4 Channel Models

Energy Conserver

Whether awake or asleep, the QX-280 amplifiers are not hungry for power.

The amplifier functions across the power range at an 89.5% efficiency rate.

With a sleep mode mains current draw of less than 0.5 watts per amplifier channel.

This is a great benefit for venues with a high amplifier channel count.

The automatic standby functionality mutes an individual amplifier channel after no signal has been detected for 10mins or more; and will put the amplifier into sleep a modeafter 30mins.

Automatic standby can be turned on and off for individualchannels via a switch located on the rear panel.

The operational voltage range of the QX-280 Series is also wide ? from 85 to 265VAC, and no manual switching is required for high and low impedance operation.

This is a great reliability benefit for installations subject to inconsistent mains supply.



  • Peak Output Current
  • THD+N (1kHz @ 1W / 1kHz ½ Rated Power)
0.022% / 0.015%
  • Dynamic Range
  • Output Resistance (1kHz)
43.6m ohm
  • Peak Output Voltage (unloaded)
  • Power Output
4 ohm 280W
8 ohm 245W
70V 250W
100V 240W
  • DC Offset
  • Frequency Response
±0.1dB 20Hz - 20kHz (1st order 22kHz LPF)
  • Voltage Gain (@ 1kHz)

Mechanical Specifications
  • Net Weight
QX1280 - 4.5kg QX2280 - 4.9kg QX4280 - 5.7kg
  • Gross Weight
QX1280 - 7.1kg QX2280 - 7.5kg QX4280 - 8.3kg
  • Dimensions (H x W x D)
44 x 485 x 304mm
  • Input Connections
3-Way 5.08mm Captive Screw Connector
  • Output Connections
2-Way 5.08mm Locking Captive Screw Connector
  • Mains Power Connection
  • Mains Input Voltage
85 - 265VAC

* All specifications were measured at 240VAC

** Quest Engineering reserves the right to make changes in specifications, or products without prior notice.

*** The figures shown above are ‘real world’,usable specifications and are conservative as a result.

  • Quest Engineering does not believe in portraying misleading or exaggerated specifications.