Inner Workings - QSC DCA1222 User Manual

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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,
ain
wide air tunnel in front of the fan for optimum cooling.
A thermal sensor embedded in each channel's heat sink monitors the tem-
perature 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.
Su
The output circuitry is actively clamped during clipping for smooth and very
fast recovery. The clamp also feeds a proportional clip limiter, which actually
Power
ontro
senses the depth of clipping and responds accordingly.
The balanced inputs use premium 0.1% precision resistors for very high noise
ut
rejection. The precision components used in the input fi lters and all other
ut
circuitry ensure accurate performance.
Shutdown. The amplifi er mutes as soon as power is shut off, preventing turn-
au t onitor
off noises. Serious faults trigger a shutdown of the power supply; the high
switching frequency cuts off power within microseconds to limit damage.

INNER WORKINGS

内部工作元件
高性能音频。高速功率晶体管可以将此 DC 电源变换为驱动扬声
器的全频音频输出。高电流设计和特别双传感输出反馈可纠正扬
声器端子两侧的误差，改进扬声器运行的阻尼和控制。电源设备
直接安装在隔离的吸热器上方，在风扇前方形成短而宽的气流通
道，从而实现最佳散热效果。
每个声道的吸热器中嵌入的热量传感器都可以监控温度并控制风
扇速度、热量降低和偏压控制，确保在所有温度和信号水平下的
最大音频清晰度。还有一个电路用于监视晶体管散热，并只有在
实际需要时才触发保护性降低。
输出电路在削波期间得到主动钳位，以实现顺利和非常快速的恢
复。钳位电路还可馈送到比例削波限制器，这实际上感测到削波
深度并相应地做出响应。
平衡输入端使用顶级 0.1% 精确度电阻，可杜绝大部分噪音。输
入滤波器和所有其他电路中使用的精确组件可确保精准的性能。
关闭。放大器在电源关闭后就处于静音状态，从而避免关闭噪
音。严重故障将触发电源关闭；高开关频率可在几微秒内切断电
源，以限制损坏程度。