LED Indicators

The LED indicators can be used to monitor system operation and identify common problems.

POWER (PWR): BLUE

Normal indication:

•AC switch ON: LED will illuminate.

If no indication:

•Check AC power cord and AC outlet.

•Confirm that AC switch is in ON position.

CLIP: RED

Normal indication:

•Illuminates whenever the amplifier is driven beyond full power. The resulting distortion corre- sponds to the brightness of the LED. Distortion that causes only brief flashing may not be audi- ble.

•During muting, the red LED fully illuminates. This occurs during normal "On-Off" muting.

Abnormal indication:

•Bright red illumination while the amp is being used indicates either thermal muting or a shorted output.

•If the amplifier overheats, the fan will run at full speed, and operation should resume within one minute. Allow the fan to run, and make sure the amplifier ventilation is adequate.

•A shorted or overloaded output circuit will cause excessive Clip flashing and possible overheat- ing.

•If distortion is audible without a Clip indication, the problem is either before or after the ampli- fier. Check for damaged speakers or overloaded signal source. The amplifier Gain control should be in the upper half of its range to prevent input overload.

SIGNAL (SIG), -10: GREEN

Normal indication:

•The SIG (signal) indicator illuminates when the input signal exceeds -35 dB, and the -10 (-10 dB) indicator illuminates when the signal exceeds -10 dB.

If no indication:

•Check Gain settings and increase gain if necessary. Check input connections and audio source for signal. If the Clip LED illuminates with little or no Signal indication, check the output wiring for shorts.

Abnormal indication:

•If the SIG or -10 LED illuminates with no signal input, there may be system oscillations or some other malfunction. Disconnect the load and fully reduce the gain. If the LED remains on, the amp may need servicing.

BRIDGE MONO (BR M) and PARALLEL (PAR) (PLX 1802/2502/3102/3602 models only):

•Each channel pair has a AMBER LED for Bridge Mode, and a AMBER LED for Parallel mode. These show how the rear panel INPUT CONFIGURATION switch is set (see Input Configuration Switch). In Stereo mode, both LEDs should be OFF. In bridge mode the BR M indicator will be illuminated. In parallel mode, the PAR indicator will be illuminated.

LED indicators on PLX 1104 and PLX 1804 models

LED indicators on PLX 1802, PLX 2502, PLX 3102, and PLX 3602 models

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QSC Audio PLX 1104 user manual LED Indicators, Power PWR Blue, Clip RED, Signal SIG, -10 Green
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PLX 1104 specifications

The QSC Audio PLX 1104 is a versatile and powerful power amplifier designed to meet the demands of live sound applications, installations, and more. Renowned for its exceptional performance and reliable operation, the PLX 1104 has become a preferred choice for sound engineers and audio professionals alike.

One of the standout features of the PLX 1104 is its lightweight design. Weighing in at just 10.5 pounds, this amplifier is easy to transport and install, making it ideal for mobile applications. Its compact form factor allows for efficient use of space in equipment racks and allows for quick setups and takedowns during events.

The QSC PLX 1104 outputs an impressive 1,000 watts per channel at 8 ohms and 1,200 watts at 4 ohms, providing ample power for driving a wide range of loudspeakers. This capability makes it suitable for various applications, from small clubs to larger venues requiring robust sound reinforcement. The amplification system utilizes a high-efficiency design that significantly reduces power consumption and heat generation, enhancing reliability and longevity.

In terms of connectivity, the PLX 1104 features balanced XLR inputs and Neutrik Speakon outputs, ensuring compatibility with a broad array of sound systems. Its intuitive control layout, including a rear-mounted gain control for each channel, allows for easy dial-in of the desired output level.

The PLX 1104 employs QSC's advanced proprietary technology to deliver exceptional audio quality. This includes sophisticated output transistors and a high-frequency protection circuit, ensuring that the amplifier provides clean and undistorted sound, even at high output levels. Furthermore, the built-in thermal management system helps to prevent overheating, further increasing the reliability of the amplifier in demanding environments.

Additional features of the PLX 1104 include a switchable low-frequency filter that can help to improve the overall clarity of sound, particularly in live sound scenarios where low-end muddying can occur. The amplifier is also equipped with a front-panel LED status indicator that serves as a visual cue for the operational status of the unit.

In summary, the QSC Audio PLX 1104 is a testament to modern amplifier technology, combining lightweight portability with powerful performance and rich features. Its ability to deliver high-quality audio while being exceptionally user-friendly makes it a go-to solution for audio professionals who require both reliability and flexibility in diverse sound reinforcement situations.
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