Specifications

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Features
• Barrier strip output connectors
• Direct transformerless 70-volt outputs (“V” models)
• Zero inrush current—won’t trip circuit breakers at turn-on and avoids need for sequential power-up
• DataPort for use with QSControl and amplifier accessories
• Independent, user-defeatable clip limiters
• Fully selectable low-frequency filtering; choice of 33 or 75 Hz roll-off or 50 or 75 Hz roll-off (“V” models)
• Stereo (dual-channel), parallel-input, or bridged mono operating modes
• Balanced inputs: XLR and “Euro-style” detachable terminal blocks
• Recessed, detented gain controls with security cover
• Front panel LED indicators for power, signal, -20 and -10 dB, clip/protect, parallel inputs, and bridged mono mode
• QSC’s exclusive high-performance PowerWave switching technology power supply
• Optional isolated output transformer pack IT-42 available for driving 2-channel 25-, 70-, and 100-volt lines, or 50, 140, and 200-volt
lines in bridged mono (CX 302 only).
The inner workings
An impressive amount of technology is packed “under the hood” of a CX Series amplifier. Thousands of watts
of power flow inches away from state-of-the-art low noise inputs. Precise circuit layout and thorough protection
assure that all of this activity occurs smoothly and safely. So, what actually happens when you turn on the power
switch?
Soft Start Sequence. The first task is to charge the primary energy reservoir without drawing a large surge
current. A special inrush limiter allows just enough current to charge the energy bank in three seconds.
Meanwhile, a low-power switching supply provides power to start up the main supply. After three seconds, a
relay bypasses the inrush limiting and full power operation is enabled. The audio circuitry
mutes for one second to eliminate start-up thumps. When the red CLIP lights go out, the
amplifier is ready for action.
PowerWave™ Technology. High current switching devices draw over 10,000 watts of
peak power from the main energy reservoir, which is replenished directly from the AC line
for maximum stiffness. Conventional amplifiers must isolate the energy bank with a large
AC transformer, which weakens the flow of current, allows greater sag under load, and
produces hum. The PowerWave supply performs voltage conversion at a very high
frequency, allowing better coupling through a much smaller isolation transformer.
High Performance Audio. High speed power transistors convert this DC power into the
full range audio output which drives the speakers. High-current design and special dual-
sense output feedback corrects errors on both sides of the speaker terminals, improving
damping and control of speaker motion. The power devices are directly mounted to isolated
heat sinks, which form a short, wide air tunnel in front of the fan for optimum cooling.
A thermal sensor embedded in each channel’s heat sink monitors the temperature and
controls fan speed, thermal shutdown, and bias control, assuring maximum audio clarity
at all temperatures and signal levels. A circuit monitors transistor dissipation and triggers
protective cutback only when actually needed.
EMI Filter
Inrush Limiting
Main Energy Bank
PowerWave Switching
DC Supply for
Amplifier
Transformer
Control
Power
PWM
Control