Protection Systems

Both amplifier platforms are fully protected against adverse conditions, but their behavior and user adjustments are different.

PLX 1802/2502/3102/3602 models:

•Clip Limiting may be switched on the rear panel to prevent severe overdrive. This protects speakers and somewhat reduces the load on the amplifier.

•Internal current limits protect the output transistors against overloading. Peak limiting may occur at full output if using more than four 8-ohm speakers per channel, or if the speaker wiring is shorted. The red Clip LED will flash brightly, and the ampli- fier may sound distorted. If the amplifier is driven hard under these conditions, the current limit will be further reduced, causing an increase in distortion. If the amplifier appears to be losing power during peaks, check the speaker wiring and number of speakers. Using Clip Limiting will reduce this distortion, but for best results do not exceed the rated loading.

•If the amplifier stops completely for several seconds after a very loud signal, it may be overloading the AC service. This only occurs if the AC voltage sags more than 30%, and will be more likely if driving many speakers at once. Use short, heavy- gauge AC cables and do not plug too many amplifiers into a single outlet.

•In Bridge Mono, the amplifier may shut down for several seconds if driven too hard into loads less than the rated 4-ohm minimum.

•If the amplifier overheats due to prolonged overload or high external temperature, it will mute for about 30 seconds with the fan running at full speed for maximum cooling. Make sure the rear intake is getting a free flow of cool air.

PLX 1104/1804 models:

•These models have completely automatic internal protection that maintains operation even under extreme conditions.

•Overdrive distortion will cause the red Clip LED to flash. If driven constantly into clipping, internal circuitry smoothly reduces the volume to minimize distortion and stress.

•These models are rated for 4-ohm loads. Do not use more than two 8-ohm speakers per channel. Using too many speakers may trigger limiting and cause a loss of volume.

•Internal current limits protect the output transistors against overloading. Moderate overloading will trigger clip limiting, and smoothly reduce output level to prevent distortion. Severe overloading, such as driving the amplifier hard into a shorted speaker wire, may cause short, rapid muting. Check the speaker wiring for shorts if the amplifier "chatters".

•Overheating may occur due to prolonged overdrive or high external temperature. This will first trigger thermal limiting, reducing volume so that the amplifier remains below its thermal limit and keeps running. If input signals are still too high, the amplifier may eventually mute for about 30 seconds with the fan at full speed for maximum cooling. Make sure the rear intake is getting a free flow of cool air.

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QSC Audio PLX 1104 user manual Protection Systems, PLX 1802/2502/3102/3602 models
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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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