2-channel amplifier — 400 watts x 2
Our take on the QSC CMX800Va by Crutchfield's Eric Angevine
Plenty of power for your commercial sound system
The QSC CMX800Va delivers plenty of clean, reliable power for your commercial audio system. Connect it to multiple speakers and fill your establishment with background music and easy-to-hear announcements.
Plenty of input and output options let you connect the equipment you need when building your ideal system. Use it in a 70-volt system in mono mode, and you'll have 2,000 watts of clean power at your command.
- efficient 2-channel power amplifier
- power output: 400 watts x 2 or 2,000 watts x 1 bridged
- can be used to drive multiple speakers in a 70-volt commercial system
- frequency response: 20-20,000 Hz
- input options: balanced barrier strip, XLR, and 1/4" TRS
- output options: Speakon™ and removable Phoenix style I/O connectors (included)
- 10 recessed rear DIP switches:
- stereo, parallel, or bridged mode
- clip limiter on/off
- low-frequency filter on/off
- tamper-proof security cover for gain controls
- low-noise variable-speed cooling fans
- 19"W x 3-1/2"H x 15-15/16"D
- weight: 44.5 lbs.
- warranty: 3 years
- Our 60-day money-back guarantee
What's in the Box:
- 2-Channel amplifier
- 58" AC power cord
- 2 Rack-Mount brackets (installed)
- Hookup Drawings
- Important Safety Instructions
2-Channel Amplifier: The QSC CMX 800Va amplifier feature rugged class H architecture that is highly efficient to reduce AC current draw and cut down on wasted heat. CMX 800Va power ratings -
|Operation Modes||Ohm or Voltage Load||Power Rating||Frequency Response||THD|
Operation Modes: The amplifier can be set for normal Stereo operation, Parallel input Mode, or Bridge Mono Mode.
- Stereo Mode: Each channel remains independent; the amplifier may be used for two different signals.
- Parallel Mode: This setting connects both inputs together; one signal feeds both channels. Each channel's Gain control and loudspeaker connection remain independent.
- Bridge Mode: This setting combines both channels into a single channel with twice the output power. Use only the first channel's input and Gain control. Set the second channel's Gain control at minimum.
70/100V Operation: The V in the model name designates the ability to directly drive 70-volt and/or 100-volt distributed loudspeakers. The CMX 800Va can operate in 70V operation in Stereo mode or Bridge Mono mode. The CMX 800Va must be configured for Bridge Mono mode for 100V operation.
High-Current Toroidal Transformer: The CMX 800Va uses a powerful, high-current toroidal transformer and filtering to ensure generous energy reserves. This allows the amplifier to effortlessly handle high-level transients, even when driving abusive 2Ω speaker loads.
SMT (Surface Mount Technology): The CMX 800Va amplifier delivers true and accurate studio-quality sound. A full complementary output circuit using high-grade linear output devices generates accurate, flat-frequency response with low distortion. SMT (Surface Mount Technology) triples small-signal component density, enabling high power output in a 2U rack unit chassis. Unlike many other designs, CMXa output devices are directly mounted to the heat sink for optimum thermal coupling and cooling.
Balanced & Unbalanced Inputs: The QSC CMXa series amplifier provides balanced & unbalanced XLR, 1/4" TRS, and barrier strip screw terminal input connectors to connect your external audio sources. The input impedance is 20 kΩ balanced and 10 kΩ unbalanced. Balanced signals are less prone to AC hum, but unbalanced signals can be suitable for short cable runs. The signal source's output impedance should be less than 600Ωto avoid high frequency loss in long cables.
Speaker Outputs: The CMXa series amplifier offers Speakon (NL4) and terminal-block output connectors to connect your loudspeakers. The NL4 connector is designed specially for high-power speaker connections. It locks in place, prevents shock hazard, and assures the correct polarity. The terminal-block connectors can accept 18 to 10AWG speaker wire.
Independent Controls: The QSC CMXa series amplifier offers independent Attenuation Controls, Clip Limiter, and Lower Frequency Filters for each channel (1-2). These controls are configured via dip-switches on the rear-panel of the amplifier.
- Attenuation Controls: Maximum attenuation is fully counter clockwise, minimum attenuation is fully clockwise. The Attenuation controls are marked in numeric increments from ∞ to 0 (clockwise) indicating the amount of attenuation. Settings should normally be made within the lower attenuation range. The range above 14 on the attenuation scale should not be used for normal program levels, as the input headroom could be exceeded, but can be used for testing at reduced gain levels.
- Clip Limiters: Each channel has a Clip Limiter with its own on-off switch to reduce distortion. The limiter only responds to actual clipping, and automatically compensates for load and voltage variations. Clip limiting is generally recommended, especially to protect high frequency drivers.
- Low Frequency Filters: Each channel has a 12dB per octave Low Frequency Filter (30 or 50Hz) to prevent cone over-excursion, making more power available for the loudspeaker's rated frequency range. This reduces distortion and prevents amplifier overload. The Filter should only be turned off for driving subwoofers with special low frequency capability. Otherwise, unless you have filtering in the signal path preceding the amplifier, use the Low Frequency Filter
Protection Circuitry: The CMX 800Va amplifier is protected from damage during shorted outputs; automatic current limiting protects the amplifier from damage until the short is corrected. The amplifier also feature DC protection to prevent loudspeaker damage in the unlikely event of an output transistor failure. DC voltage from the power supply is never passed directly to your speakers, even in the event of an output circuit failure.
LED Indicators: The LED indicators on the front-panel of the amplifier can be used to monitor system operation and identify common problems.
- Power: A single blue indicator will illuminate when powered on; no illumination when powered off.
- Signal: A green indicator for each channel will illuminate when the input signal exceeds -35 dB. As signal approaches full power, the indicator will illuminate continuously.
- Clip: A red indicator for each channel will illuminate whenever the amplifier is driven beyond full power.
- Protect: A single red indicator will illuminate when the amplifier goes into protect mode. Under normal operation, this indicator will not be illuminated.
Cooling Fan: Cool air is drawn into the rear of the amplifier by the cooling fan. Warm air exits the front of the amplifier.
Rack-Mountable: The CMX 800Va amplifier is rack mountable (requires 2U space).
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