Description

QSC GD4 Power Amplifier

GXD4 Professional 2x 600 Watts Power Amplifier

The QSC GXD4  power amplifier series are ideal for portable sound reinforcement applications and installations with demanding DSP requirements and flexibility at a cost effective price. This high performance line consists of two amplifiers, the GXD4 and GXD8, each providing enormous Class-D power in a lightweight and efficient package.  The universal switch mode power supply helps reduce the weight, increase efficiency, and ensures rock-solid continued operation even with poor power conditions.  The addition of on-board DSP processing with an easy-to-use interface offers powerful tools like Crossover and EQ filters, Delay, and Power Limiting that allow the user to configure the amplifier and maximise the performance of their loudspeakers.   The GXD Series amplifiers are engineered to meet any demanding application and provide excellent power and legendary QSC reliability, in an efficient, lightweight, and flexible package; bottom line, the GXD amplifiers provide outstanding value!

There’s a GXD amplifier within 1dB of the ideal power for your speaker system. Best practice is to use an amplifier capable of delivering approximately twice the loudspeaker’s rated power capacity. Too little amplifier and the speakers won’t deliver everything they’re capable of and the risk of destructive amplifier clipping is increased. Too much power probably means unnecessary amplifier expense.

To determine the power points for the GXD series, QSC examined the loudspeakers most widely used for sound reinforcement by musicians, DJs and production professionals. Overall, these speakers are equipped with woofers that fall into a couple of categories of continuous power capacity – low-power drivers that can handle 150 – 250 watts, and mid to high-power drivers rated around 250-400 watts. Single woofer loudspeaker systems using these drivers will typically have an impedance of 8Ω. Dual woofer loudspeakers will, of course, have power ratings that are two times that of the single woofer model and an impedance that is half that of single-woofer models.

Digital Signal Processing

The GXD amplifiers are unlike other amps in this category that provide little more than a front panel screen to control the same functions that have been under rear-panel, DIP switch control for decades. The GXD amps bring full-function loudspeaker processing capability to a new price point with all the processing necessary to get the most from a loudspeaker system. The DSP section includes High and Low-Pass filters (24dB LR), 4-band parametric equalizer, signal alignment delay, and RMS/Peak speaker protection limiting. Twenty presets for selected typical systems are provided as generic “starting points” are included.

Digital Limiting

The most common cause of loudspeaker failure is amplifier clipping. The digital limiter used in the GXD amplifiers is set to prevent the amplifier from being driven into clipping while delivering the maximum usable output. In addition to amplifier limiting it also provides smart speaker protection by simply setting the loudspeaker’s continuous power and impedance (4Ω and 8Ω), and selecting whether Mild, Medium or Agressive protection is desired.

E Series Entertainment System

The GXD amplifiers are part of the E Series Entertainment System and include loudspeaker tuning to maximise the performance of the E Series loudspeakers. Processing functions include Crossover and EQ settings as well as Limiter settings to ensure that the system performs sonic-ally and protects your loudspeaker investment.

Product Specifications

General

• 8Ω dynamic, both channels driven:  600 watts per channel
• 4Ω dynamic, both channels driven:  800 watts per channel
• 8Ω continuous, both channels driven:  400 watts per channel
• 4Ω continuous, both channels driven:  600 watts per channel
• Distortion (typical) 1 kHz at full rated power:  < 1% THD
• Signal to Noise (A weighted, 20 Hz–20 kHz):  100 dB
• Input Sensitivity:  1.2 Vrms, 3.9 Vrms
• Maximum Voltage Gain:  33.5 dB
• Output Circuitry:  Class D
• Power Requirements:  1/8 power at 4Ω
• 100 V AC:  3.4 A
• 120 V AC:  2.9 A
• 230 V AC:  1.6 A
• Frequency Response (20 Hz–20 kHz):  +0.7 dB, -0.8 dB
• Dynamic Headroom (4Ω):  1.25 dB
• Damping Factor (8Ω):  100
• Input Impedance:  20 kΩ (balanced), 10 kΩ (unbalanced)
• Maximum Input Level:  +23.5 dBu
• Input Connectors (each channel):  3-pin XLR/F / 1/4″ TRS, balanced
• Output Connectors (each channel):  NL4, binding posts; NL4 pinout: Channel A on 1+, 1-; Channel B on 2+, 2-  |  Channel B on 1+, 1-
• Amplifier and Load Protection:  Short circuit, open circuit, thermal, RF protection  |  Load protected against DC faults

Front Panel Controls and Indicators

• 2 × Rotary Encoders
• 3 × Operational buttons (HOME, ENTER, EXIT)
• 2 × Green Signal LEDs indicate signal presence
• 2 × Red A/D Clip LEDs indicate input over-drive and/or amplifier current clipping

DSP Functions

• High-pass filter, 4th-order Linkwitz-Riley, adjustable frequency 20 Hz to 4 kHz
• Low-pass filter, 4th-order Linkwitz-Riley, adjustable frequency 60 Hz to 4 kHz
• 4-band parametric EQ with variable frequency, gain, and bandwidth
• Peak limiter with power, aggressiveness, and impedance selection
• Delay 50 msec max.

Physical & Dimensions

• Height:  2 RU 89 mm
• Width:  483 mm
• Depth:  259 mm
• Weight (Net):  5.1 kg
• Weight – Shipping:  7.0 kg