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11

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.

Содержание PLX 1802

Страница 1: ...fiers User Manual 4 ohm minimum impedance models with Speakon output terminals PLX 1104 PLX 1804 2 ohm minimum impedance models with Speakon and binding post terminals PLX 1802 PLX 2502 PLX 3102 PLX 3...

Страница 2: ...er to the risk of hazardous energy Output connectors that could pose a risk are marked with the lightning flash Do not touch output terminals while amplifier power is on Make all connections with ampl...

Страница 3: ...d 21 step detented Active inrush current limiting eliminates need for power sequencing LED indicators for power input signal presence 10 dB and clip protect Rear chassis tabs and front panel design pr...

Страница 4: ...om QSC s Technical Services Group The cast front panel includes finger grips at each end mak ing lifting and setting into the rack more comfortable 1 Input Configuration switch 2 1 4 inch TRS input co...

Страница 5: ...Draw The table at the right provides typical current draw for each model as a function of load and output power level Units of measurement are amperes rms NOTE Current draw shown is for 120 VAC line F...

Страница 6: ...the clip limiter Low Frequency Filters PLX 1802 2502 3102 3602 models only Each channel has independent filter selection of Full Range infrasonic filter only 33 Hz low cut 100 Hz low cut or 100 Hz Hi...

Страница 7: ...The signal s source impedance should be less than 600 ohms Input Pinouts Balanced inputs Connect to the plug as shown XLR TRS Unbalanced inputs Connect to the plug as shown If using an XLR connector...

Страница 8: ...tput connection Bridge mode configures the channel pair to drive a single high power loudspeaker load The INPUT CONFIGURATION switch must be set for BRIDGE mode Use only Channel 1 s input and Gain con...

Страница 9: ...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 indi...

Страница 10: ...reduced levels At the minimum setting the signal is completely cut off Note The GAIN controls do not adjust the power of the amplifier They adjust its sensi tivity to input signals Gain controls and...

Страница 11: ...riven 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...

Страница 12: ...ack to front air flow through heat sink array CONTROLS Front AC POWER switch Gain controls each channel 21 detents Back AC circuit breaker LED INDICATORS POWER blue SIGNAL green x 2 10 dB green x 2 CL...

Страница 13: ...o reactive or mismatched loads COOLING Continuously variable speed fan back to front air flow through heat sink array CONTROLS Front AC POWER switch Gain controls each channel 21 detents Back Input Co...

Страница 14: ...Speakon Wiring Reference Amplifier connection To loudspeaker Two wire single channel connection Four wire two channel connection Bridge mode connection NOTE Ensure proper polarity when connecting brid...

Страница 15: ......

Страница 16: ...taktinformationen f r QSC Audio Products QSC Audio Products Mailing address QSC Audio Products Inc 1675 MacArthur Boulevard Costa Mesa CA 92626 1468 USA Telephone Numbers Main Number 714 754 6175 Sale...

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