PLX Series Professional Audio Amplifiers 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 3602 *TD-000214-00* TD-000214-001Rev.C Important Safety Precautions & Explanation of Symbols 1- Read these instructions. 2- Keep these instructions. 3- Heed all warnings. 4- Follow all instructions. 5- WARNING: To prevent fire or electric shock, do not expose this equipment to rain or moisture. Do not use this apparatus near water. 6- Clean only with a dry cloth. 7- Do not block any ventilation openings. 8- Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat. 9- Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades with one wider than the other. A grounding plug has two blades and a grounding prong. The wide blade or third prong are provided for your safety. If the provided plug does not fit your outlet, consult an electrician for the replacement of the obsolete outlet. 10- Protect the power cord from being walked on or pinched, particularly plugs, convenience receptacles, and the point where they exit from the apparatus. 11- Use only attachments/accessories specified by QSC Audio Products, Inc. 12- Use only with hardware, brackets, stands, and components sold with the apparatus or by QSC Audio Products, Inc. 13- Unplug the apparatus during lightning storms or when unused for long periods of time. 14- Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged in any way, such as power supply cord or plug is damaged, liquid has been spilled or objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally, or has been dropped. The exclamation point within an equilateral triangle is intended to alert the user to the presence of important operating and maintenance (servicing) instructions in this manual. The lightning flashes printed next to the OUTPUT terminals of the amplifier are intended to alert the user 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 amplifier turned off. The lightning flash with arrowhead symbol within an equilateral triangle is intended to alert the user to the presence of uninsulated "dangerous" voltage within the product's enclosure that may be of sufficient magnitude to constitute a risk of electric shock to humans. CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE THE COVER. NO USER-SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED PERSONNEL. WARNING: To prevent fire or electric shock, do not expose this equipment to rain or moisture. FCC INTERFERENCE STATEMENT NOTE: This equipment has been tested and found to comply with the limits for a class B digital device, pursuant to part 15 of the FCC rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses, and can radiate radio frequency energy and if not installed and used in accordance to the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by switching the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures: ·Reorient or relocate the receiving antenna. ·Increase the separation between the equipment and the receiver. ·Connect the equipment into an outlet on a circuit different from that to which the receiver is connected. ·Consult the dealer or an experienced radio or TV technician for help. © Copyright 2006, QSC Audio Products, Inc. QSC® is a registered trademark of QSC Audio Products, Inc. "QSC" and the QSC logo are registered with the U.S. Patent and Trademark Office Speakon® is a registered trademark of Neutrik Inc. All trademarks are the property of their respective owners. 2 Introduction Thank you for purchasing this QSC power amplifier. Please read the following directions to obtain the best results. This manual covers all models of the PLX series. Illustrations show the PLX 1804 to be representative of the PLX 1104 and 1804 models, while the PLX 3602 illustration is representative of the PLX 1802, PLX 2502, PLX 3102, and PLX 3602 models. The PLX 1104 and PLX 1804 models feature: ·4-ohm minimum impedance ·Speakon loudspeaker connections ·QSC PowerLight high-performance, compact, and light weight switching power supply ·Complete amplifier protection ·XLR and 1/4-inch TRS balanced input connectors ·Gain controls are recessed and 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 protect controls and connectors In addition, the PLX 1802, PLX 2502, PLX 3102, and PLX 3602 models feature: ·2-ohm minimum impedance ·Bridgeable output ·Binding post loudspeaker connections ·Clip limiter ·33 Hz low frequency filter ·Low-cut/full-range/high-cut selector ·Stereo/bridge mode/parallel input selector ·Front panel LED indicators for parallel and bridge modes Unpacking Factory packed carton contains: ·PLX amplifier ·User's manual ·Adhesive rubber feet (for non-rack mount applications) ·IEC-type detachable power cord Use the same type carton when shipping the amplifier. Front Panel 1- Power Switch 2- Cooling Air Exhaust Vents 3- LED Indicators 4- Gain Controls 3 Rear Panel 1- Input Configuration switch 2- 1/4-inch TRS input connectors 3- XLR female input connectors 4- Low Frequency Filter switches 5- Speakon output connectors 6- Binding post output connectors 7- Cooling air inlet vents 8- Clip Limiter switch 9- Serial number plate 10- IEC-type AC mains inlet 11- Circuit breaker, resettable Rack Mounting Use four screws and washers to mount the amplifier to the equipment rack rails. To use the amplifier outside a rack, attach the self-adhesive rubber feet to the bottom. For portable, mobile, or other applications where the rack assembly may be moved, we strongly recommend supporting the rear of the amplifier. A rear rack ear kit is available from QSC's Technical Services Group. The cast front panel includes finger grips at each end, making lifting and setting into the rack more comfortable. The front panel casting includes features for finger-lifting and gripping at each end. 4 Cooling Air flows from the rack, into the back of the amplifier, and out the front. This keeps the rack cool. The fan automatically runs faster when the amp is working hard. Air flow in QSC amplifiers: Cool air is drawn into the rear of the amplifier by the cooling fan. Warm air exits the front of the amplifier. Do not block the front or rear air vents! AC Mains Connection Connect AC power to the IEC socket on the back of the amplifier. NOTE: Turn off the AC power switch before connecting AC power. Connect the AC mains plug to a suitable AC mains outlet. The correct AC line voltage is shown on the serial number label, on the rear panel. Connecting to the wrong line voltage may damage the amplifier or increase the risk of electric shock. The rear chassis ear can be used to retain the IEC power connector. After inserting the IEC block into the receptacle, use a wire-tie or similar device to secure the cord to the chassis ear. Orient the IEC connector with the connector prongs in the socket, then push the connector firmly into the IEC socket until fully seated. AC Mains Current 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. For 230 VAC models, multiply values shown by 0.5. ·1/8 power (pink noise) represents typical program with occasional clipping. Use this rating for most applications. ·1/3 power (pink noise) represents severe program with heavy clipping. ·Full power (sine) is continuous sine wave driven at 1% clipping. ·PLX 1802, PLX 2502, PLX 3102, and PLX 3602 models: Thermal or overcurrent cutback limits duration of full power 2 ohm operation. Long term, active limiting to 30A at 120V. ·PLX 1104 and PLX 1804 models: Long-term, circuit breaker limited to 15A at 120V. 5 Input Configuration Switch (PLX 1802/2502/3102/3602 models only) Select the input configuration by sliding the switch to the position which corresponds with the desired input configuration. ·Bridge- upper position ·Stereo- middle position ·Parallel- lower position Stereo Mode: Each channel remains independent, and each may be used for a different signal. Parallel Mode: This setting connects both inputs together. One input signal feeds both channels. Do not connect different sources to each input. Each channel's Gain control and speaker connection remain independent. Bridge Mode: This setting combines both channels into a single channel with twice the output voltage. Use only Channel 1's input and Gain control. Set Channel 2's Gain control at minimum. Use only one input when operating in parallel or bridge mode. Low Frequency filter selection switches for each channel Clip Limiter ON/OFF switch Input Configuration selector switch Clip Limiters (PLX 1802/2502/3102/3602 models only) The amplifier has a clip limiter with an on-off switch. The limiter only responds to actual clipping, and automatically compensates for load and voltage variations. Clip limiting is generally recommended, especially to protect high frequency drivers. ·Set the switch UP (ON position) to use Clip Limiting. ·Set the switch DOWN (OFF position) to disable 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 High Cut. This allows tailoring the amplifier performance to that of the loudspeakers, offering the best possible performance from the system. Proper filtering reduces distortion and prevents amplifier overload. TOP / FULL / SUB Switch: Select the type of loudspeaker being driven by each channel. ·Set the switch to the left for driving "top" boxes; applies 100 Hz low cut ·Set the switch to the middle position for "full range" loudspeakers. ·Set the switch to the rightmost position for driving subwoofers. Low Frequency filter selection table 33 Hz (low cut) / FULL Switch: Unless the loudspeaker has extended low frequency capability, we recommend setting the filter to the 33 Hz setting. The filter should only be set to FULL (turned off) for driving subwoofers. Check the loudspeaker's specifications and use the 33 Hz filter if the loudspeaker's low frequency capability does not extend below 33 Hz. ·Set to FULL when driving loudspeakers that have low frequency capability below 33 Hz or in studio monitoring applications. ·Set to 33 Hz for loudspeakers which are not rated for frequencies below 33 Hz. 6 Inputs Each channel has a balanced XLR (female) and 1/4-inch TRS input. The XLR and TRS connectors for each channel are wired in parallel and can be used for "daisy chaining" an input signal to additional amplifiers. The input impedance is 20k ohm balanced or 10k ohm unbalanced. Both XLR and TRS inputs are connected with standard cables and can be changed quickly. Pinouts are marked on the rear panel. Do not attempt to connect more than one input signal to a given channel. Balanced connections are recommended to reduce AC hum and interference, especially with long cable runs. Unbalanced connections may be suitable for short cables. The signal's source impedance should be less than 600 ohms. Input connectors and pinout chart (PLX1802 shown) Input Pinouts Balanced inputs: Connect to the plug as shown. XLR TRS PLX 1104 and PLX 1804 models can parallel the input signal to both channels by using a jumper from one channel to the next: Unbalanced inputs: Connect to the plug as shown. If using an XLR connector, Pin 3 and pin 1 must be connected with a jumper as shown. If using a TRS connector, the ring and sleeve must be connected with a jumper. If a TS connector is used, the sleeve will provide the "jumper" when inserted into the input jack. ·Connect the input signal to either of Channel 1's input connectors. ·Connect a jumper from Channel 1's unused connector to either of Channel 2's input connectors. Input signal XLR TRS TS TRS to TRS jumper from Channel 1 to Channel 2 7 Outputs The PLX 1104 and PLX 1804 models are equipped with Speakon ...