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QSC GX3 Stereo Power Amplifier

OSC GX3 amplifiers are ideal for professional entertainers who demand maximum performance and portabilit, all on a limited budget.


(17 reviews)


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MSRP: Old Price $439.00 Discounted Price $349.99 Save : $89.01 (20%)
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MSRP: Old Price $439.00 Discounted Price $349.99 Save : $89.01 (20%)
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The QSC GX3 stereo power amplifier have optimized output and appearance while reducing raw material cost and weight. It's all here – dramatic styling, easy hookup and adjustments, excellent audio quality and QSC reliability.

QSC GX3 stereo power amplifiers deliver just the right amount of power to the most popular speakers used by entertainers. Most loudspeaker manufacturers 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. The GX3 is ideal for speakers in the 300 watt (Program) range, supplying maximum possible power to 4 ohm and 8 ohm loads.

Technical Notes
The GX3 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.

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 music, protect the speakers and keep the audience excited, without unprofessional distortion levels or shutdowns.

Subwoofer/Satellite Crossover
A subwoofer reduces strain on the full-range speaker, allowing it to play louder, or letting a smaller speaker do the same job. The GX Series 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.

  • 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 (10.1" / 257 mm) fits in compact, inexpensive effects racks  
  • Lightweight – less than 26 lbs (12.5 kg)  
  • 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

  • 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  34.4 dB
  • Output Circuitry Class B
  • Power Requirements (1/8 power, pink noise at 4 ohms, 120V)  6.3A
  • 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)
  • Input Connectors (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
  • Front Panel Controls and Indicators  Gain controls, 21 detents; 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)

Things You Will Get:

    GX3 Power Amp
    Power Cable
    Owner's Manual



Works great. Plenty of power. Definitely recommend it.



Great, clean sound


I bought two of these to power the four passive speakers in the corners of my piano studio. At 300 watts a side, they supply more than enough great, clean sound.



Great Amp for Keyboard


My old (30 Yr. Old) QSC amp was having some problems so I decided to update/upgrade to the GX3 amp. Pleanty of volume/headroom for my Korg Kronos Keyboard. Easy to use and set up. Great Product and Sam Ash was great as usual.




Buy and amp that will last you forever..


QSC has been the innovator and keepers of the legacy of sound since they started. Their one goal was to make power amps that lasted, sounded great and were at the top of their class. With the GX series, they continue that tradition. Not only does this amp sound good, it is super light, making it portable. With the features and how great it sounds, it makes it easy to use and for a novice to seem like a experienced professional. Plus QSC backs this up with a 6 year no-fault warranty. You need not look anywhere else when looking for an amp. " This is a real hands-on review from Jamie at Sam Ash Indy."


Indianapolis, IN


Great powerful amp for the Price!!!


Great powerful amp from QSC!! Lightweight and puts out the power!! Built in crossover for easy use with a sub! Ideal for speakers in the 300watt range. Good amp for the price!! "This is a real hands on product review from [email protected] Sam Ash Orlando"

Billy B



Great quality power


Professional quality power that provides excellent warm tone. Nice and easy to use and very dependable. I am a staff reviewer at Sam Ash Music




An Easy to Use Stereo Power Amp


The QSC GX3 Stereo power amplifier is made to be straight forward and easy to use. It's power output ratings can easily be paired with some of the most popular passive speakers on the market today. It has great sound quality and it has a built in crossover for Sub/Satellite configuration of your speakers. This is a real hands on product review from [email protected] Sam Ash King of Prussia.


King of Prussia PA


Great power amp


The GX3 is a great power amp to push any passive speaker you have. You'll never have to worry abou these failing because of the quality construction. Easy to use. This is a hands-on product review by Tamir @ Sam Ash Edison


Edison, Nj


Awesome Amp


Awesome power amp for the price. Good, stable power output and extremely reliable. This is a hands on review from Dylan @ Sam Ash Sarasota




Very awesome amplifier!


The QSC GX3 Stereo Power Amplifier is a great powerful amplifier to really get your speakers up and running! This is great for a medium to large venue. It is solidly built so you don't have to worry about it being destroyed, but yet it doesn't weight too much as well. The sound is great. This is a real hands on product review from Scott @ Sam Ash Queens

The Bearded Guy

Queens, NY


GX3 Stereo Power Amplifier

4.8 17


Inputs 3-pin XLR and 1/4" TRS, balanced, parallel; Phono, unbalanced
Series GX
Other Features GuardRail™ automatically protects the amplifier and loudspeakers from damage due to temperature rise or overdrive without shutting down the show
Model GX3 ,  3
Rack Spaces 2U
Channels 2
Weight 16.5 lbs (7.5 kg)
Dimensions 19"W x 3.5"H x 10.1"D
Power Class Class B
Watts/Side @ 4 ohms 425 W Stereo / 500W Bridge Mono
Watts/Side @ 8 ohms 4 ohms / 1 kHz (single channel driven)
Outputs Speakon®, 1/4", Binding Posts
Warranty Info:

GX3 Stereo Power Amplifier

The manufacturer's warranty covers parts and labor for six years from date of purchase. The warranty excludes damage from misuse, abuse, and contains other exclusions.

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