QSC GX3 2-Channel 300W Power Amplifier

The GX3 2-Channel 300W Power Amplifier from QSC is ideal for speakers in the 300-watt (Program) range. It uses QSC’s cutting-edge Grounded Collector output system to achieve optimum cooling of the critical power transistors. The GX3 features a built-in subwoofer/satellite, as well as detented gain controls that allow for precise settings and let you exactly match sensitivity levels. Additionally, an integrated GuardRail™ protects the amplifier and loudspeakers from damage due to rises in temperature or overdrive—without shutting down the entire show. Meanwhile, a true Class B biasing system pairs maximum thermal efficiency with excellent audio performance.

Enjoy optimal versatility and durability. The GX3’s low-profile chassis makes it easy to fit into compact, inexpensive effects racks. The front panel boasts LEDs to help monitor power, signal, and clipping at a glance. It includes XLR, ¼” TRS, and phono input connectors to provide compatibility with any source, while it also includes Speakon® combo connectors that accept 1/4-inch (TS) plugs or Speakon 2- and 4-pole plugs (connects 2 poles only) outputs, as well as binding posts to support all other speaker wiring systems.

More about QSC’s GX Power Amplifiers

Like all QSC’s products, the GX series of power amplifiers are characterized by professional-quality audio, meticulous engineering, precision manufacturing, and long-term reliability. The GX series was designed for professional entertainers who require a true technological trifecta from their audio gear: an affordable power amp that delivers high-quality performance in a portable build. GX Series amplifiers are fully protected from the usual hazards of the trade, ensuring stable performance and the long life that’s demanded by touring performers.

GX power amplifiers boast multiple input/output options for enhanced flexibility and advanced protection circuitry, all in a feature-packed build that’s lightweight, easy to integrate into any size setup, and sports a contemporary look. Most importantly, GX amps provide the perfect amount of power to the most popular loudspeakers that are used in the entertainment industry. For example, loudspeaker manufacturers typically recommend an amplifier with power output equal to the speaker’s “Program (Music) Power” rating or two times (2 x) the “Continuous (RMS) Power” rating.

QSC GX3 Features

• Power levels matched to the most popular speakers used by entertainers
• Optimized for maximum real-world headroom into 4Ω and 8Ω speaker systems
• Inputs: XLR, ¼" TRS and phono input connectors for compatibility with any source
• Outputs: Speakon® combo accepts, ¼" (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 (10.1"/257 mm) fits in compact, inexpensive effects racks
• Lightweight
• Detented gain controls for precise setting and matching of sensitivity
• GuardRail™ automatically protects the amplifier and loudspeakers from damage due to temperature rise or overdrive without shutting down the show
• Front panel LEDs monitor Power, Signal and Clipping
• Subwoofer/Satellite crossover built-in

• GX3 2-Channel 300W Power Amplifier1

• Output power per channel
  • 8Ω continous, both channels driven: 300W
  • 4Ω continous, both channels driven: 425W
• Distortion (1 dB below rated power, 1 kHz)
  • 8Ω: less than 0.02%
  • 4Ω: less than 0.05%
• Signal to Noise (20 Hz - 20 kHz)100 dB
• Input Sensitivity1.2V rms
• Voltage Gain32.2 dB
• Output CircuitryClass B
• Power Requirements (1/8 power, pink noise at 4 ohms, 120V)6.3A
• Frequency Response20 Hz–20 kHz, +0, -1 dB
• Dynamic Headroom (4 ohms)2 dB
• Input ImpedanceGreater than 20 kΩ (balanced)
• Maximum Input Level+24 dBu (16 V rms)
• Input Connectors (each channel)
  • 3-pin XLR and 1/4-inch TRS, balanced, parallel
  • Phono, unbalanced
• Output Connectors (each channel)Speakon®, 1/4-inch, Binding posts
• Amplifier and Load Protection
  • Short circuit, open circuit, thermal, RF protection
  • Load protected against DC faults
• Front Panel Controls and Indicators
  • Gain controls, 21 detents
  • Red CLIP LEDs, proportional, 0.1% THD threshold
  • Green SIGNAL LEDs, threshold 35 dB below clipping
  • Blue POWER LED, AC on
• Rear Panel Controls
  • Full Range / Crossover switch
  • Full Range / Crossover switch
• Product Dimensions (H×W×D)3.5 × 19 × 10.1 in (89 × 483 × 257 mm)
• Carton Dimensions (H×W×D)24 × 15 × 6 in (610 × 380 × 153 mm)
• Net Weight27 lbs (12.1 kg)
• Shipping Weight29.1 lbs (13.2 kg)
• Agency ApprovalsUL, CE, RoHS/WEEE Compliant
• AC Current and Heating, 120 VAC (multiply current by 0.5 for 230 VAC)GX3
• Operating Condition
  • AC amps
  • Idle: 0.3
  • 8 + 8 ohms, 1/8 power (1): 3.3
  • 8 + 8 ohms, 1/3 power (2): 8.5
  • 8 + 8 ohms, full power (3): 16.2
  • 4 + 4 ohms, 1/8 power (1): 5.8
  • 4 + 4 ohms, 1/3 power (2): 11.2
  • 4 + 4 ohms, full power (3): 24.5
  • BTU/Hour
    • Idle: 44
    • 8 + 8 ohms, 1/8 power (1): 904
    • 8 + 8 ohms, 1/3 power (2): 1160
    • 8 + 8 ohms, full power (3): 1109
    • 4 + 4 ohms, 1/8 power (1): 1515
    • 4 + 4 ohms, 1/3 power (2): 2105
    • 4 + 4 ohms, full power (3): 2297
• Notes
  • (1) 1/8 power represents typical maximum operating conditions
  • (2)1/3 power represents over-driven program levels
  • (3)3 Full power is breaker limited to short periods
  • For 230 V, multiply AC current by 0.5
  • For 100 V, multiply AC current by 1.25