300W Per Channel (8 Ohms) Stereo Power Amplifier


The QSC GX3 professional power amplifier uses the latest evolution of the QSC Grounded Collector output system, for optimum cooling of the critical power transistors. A true Class B biasing system combines maximum thermal efficiency with excellent audio performance. 

The GX3 power amplifier is ideal for professional entertainers who require maximum performance and portability on a limited budget. QSC designers, headed by Pat Quilter, have optimized output and appearance while reducing raw material cost and weight.  This power amp is ideal for speakers in the 300 watt (Program) range, supplies maximum possible power to 4 ohm and 8 ohm loads, and features easy hookup and adjustments. 

The GX3 uses premium toroidal power transformers for reliable "mid-weight" performance.  A variable-speed fan moves air crosswise through the amplifier, drawing cool air in over the power transformer, through the fan, and then over the heat sink. This keeps the transformer cool and allows a full size heat sink to fit in a down-sized chassis.

GuardRail™ protection delivers full peak power while preventing detrimental overloads. During excessive clipping, or extreme overheating, GuardRail reduces gain just enough to preserve the integrity of the audio and protect the speakers without unprofessional distortion levels or shutdowns.

A subwoofer reduces strain on the full-range speaker, allowing it to play louder, or letting a smaller speaker do the same job. The GX3 supports this mode with a Crossover switch that splits the full-range input entering Ch 1, sending 20 Hz - 100 Hz to the sub (Ch 1) and 100 Hz - 20 kHz to the top box (Ch 2).  The front panel gain controls balance the sub and top box, while GuardRail optimizes peak power into the sub and top individually, for greater musical impact and dynamic range.

QSC GX3 Features:

  • Power levels matched to the most popular speakers used by entertainers
  • Optimized for maximum real-world headroom into 4 Ohm and 8 Ohm speaker systems
  • Inputs:  XLR, 1/4" TRS and phono input connectors for compatibility with any source
  • Outputs:  Speakon® combo accepts, 1/4" (TS) plugs or Speakon 2-pole and 4-pole plugs (connects 2 poles only).
    • Binding posts support all other speaker wiring systems.
  • Minimum-depth chassis fits in compact, inexpensive effects racks
  • Detented gain controls for precise setting and matching of sensitivity
  • Front panel LEDs monitor Power, Signal and Clipping
  • Subwoofer/Satellite crossover built-in

QSC GX3 Specifications:

  • Power:
    • 8 Ohms/1 kHz (both channels driven): 300 W
    • 8 Ohms/1 kHz (single channels driven): 350 W
    • 4 Ohms/1 kHz (both channels driven): 425 W
    • 4 Ohms/1 kHz (single channels driven): 500 W
  • Distortion (typical) 20 Hz - 20 kHz, 1 dB below rated power:
    • 8 Ohms: Less than 0.05%
    • 4 Ohms: Less than 0.1%
  • Signal to Noise (20 Hz - 20 kHz): 100 dB
  • Input Sensitivity: 1.2 Vrms
  • Voltage Gain (8 ohms): 32.2 dB
  • Output circuitry: Class B
  • Power Requirements (1/8 Power, Pink Noise @ 4 ohms, 120 V): 6.3 A
  • Frequency Response: 20 Hz - 20 kHz, +0, 1 dB
  • Dynamic Headroom (4 ohms):  2 dB
  • Damping Factor (8 ohms): 100
  • Input Impedance (ohms): Greater than 20k (balanced)
  • Maximum Input Level: +24 dB (16 Vrms)
  • InputConnectors (each channel): 
    • 3-pin XLR and 1/4" TRS, balanced, parallel
    • Phono, unbalanced
  • Output Connectors (each channel):  Speakon®, 1/4", Binding Posts
  • Amplifier and Load Protection:  Short circuit,open circuit, thermal, RF protection
  • Load protected against DC faults
  • FrontPanel Controls and Indicators: 
    • Gain controls, 21detents
    • Red Clip LEDs, proportional, 0.1% THD threshold
    • Green Signal LEDs, threshold -35 dB
    • Blue Power LED, AC on
  • Rear Panel Controls: Full Range / Crossover switch - 100 Hz, 3rd order LP (sub), 2nd order HP (top)
  • Cordset: 120V 50/60 Hz: NEMA-15
  • Dimensions (HxWxD):  3.5" x 19" x 10.1" (89 x 483 x 257 mm), 2 RU High
  • Net Weight : 25 lbs. (11.5 kg)
  • Shipping Weight: 30 lbs. (13.5 kg)
  • Agency Approvals: UL, CE, RoHS/WEEE Compliant

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