MXa Series v v v v MX 1000a MX 1500a MX 2000a MX 3000a Owner's Manual ® A U D I O *TD-000026-00* Rev. B 1 MXa Series Power Amplifier Operation Manual TABLE OF CONTENTS I. WARNING NOTICES ................................................. 3 Speaker Damage ....................................................... 3 Speaker Output Shock Hazard .................................. 3 Rack Mounting Precaution ......................................... 3 II. III. OVERALL DESCRIPTION ........................................ 4 INPUTS ...................................................................... 5 MX 1000a ................................................................... 5 MX 1500a ................................................................... 5 MX 2000a ................................................................... 5 MX 3000a ................................................................... 5 IV. OUTPUTS .................................................................. 6 Controls and Displays ................................................ 6 AC Power ................................................................... 6 V. OPERATIONS ........................................................... 6 Troubleshooting ......................................................... 7 Specifications ............................................................. 8 Open Input ArchitectureTM Level One .......................... 9 Parallel, Stereo, or Bridged Operation ..................... 10 Instructions for Bridged Operation ........................... 10 VI. LONG-TERM OUTPUT POWER ............................. 11 AC Current Consumption ......................................... 11 Heat Emissions ........................................................ 12 Protection Circuits .................................................... 12 VII. WARRANTY AND DISCLAIMERS .......................... 13 Disclaimer ................................................................ 13 Product Warranty ..................................................... 13 VIII. TECHNICAL ASSISTANCE AND SERVICE ........... 13 Technical Assistance ............................................... 13 Factory Service ........................................................ 13 Qualified Service Centers ........................................ 14 International Servicing .............................................. 14 IX. X. QSC ONLINE ........................................................... 14 IMPORTANT ADDRESS AND TELEPHONE INFORMATION ........................................................ 15 EXPLANATION OF GRAPHICAL SYMBOLS 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. The exclamation point within an equilateral triangle is intended to alert the users to the presence of important operating and maintenance (servicing) instructions in the literature accompanying the product. EXPLICATION DES SYMBOLES GRAPHIQUES Le symbole éclair avec point de flèche à l'intrérieur d'un triangle équilatéral est utilisé pour alerter l'utilisateur de la presence à l'intérieur du coffret de "voltage dangereux" non isolé d'ampleur suffisante pour constituer un risque d'elétrocution. Le point d'exclamation à l'intérieur d'un triangle équilatéral est employé pour alerter les utilisateurs de la présence d'instructions importantes pour le fonctionnement et l'entretien (service) dans le livret d'instruction accompagnant l'appareil. ERKLÄRUNG DER GRAPHISCHEN SYMBOLE Der Blitz nach unten zeigendem Pfeil in einem gleichseitigen Dreieck weist den Benutzer auf das Vorhandensein einer unisolierten, gefährlichen " Spannung" im Gehäuse hin, die stark sein kann, einer Person einen elektrischen Schlag zu versetzen. Das Ausrufzeichen in einem gleichseitigen Dreieck weist den Benutzer auf wichtige Betriebs- und Wartungsvorschriften in den beiliegenden Unterlagen des Gerätes hin. 2 CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN I. WARNING NOTICES SPEAKER DAMAGE The MXa Series amplifiers are among the most powerful professional amplifiers available and is capable of producing much more power than many loudspeakers can handle. It is the user's responsibility to use suitable speakers with the amplifier and to use them in a sensible way that will not cause damage. QSC will not be responsible for blown speakers. Consult the speaker manufacturer for power-handling recommendations. CAUTION: To reduce the rish of electric shock, do not remove the cover. No user-serviceable parts inside. Refer servicing to qualified service personnel. WARNING: To prevent fire or electric shock, do not expose this equipment to rain or moisture. AVIS RISQUE DE CHOC ÉLECTRIQUE NE PAS OUVRIR ATTENTION: Pour eviter les risques de choc électrique, ne pas enlever le courvercle. Aucun entretien de pièces intérieures par l'usager. Confier l'entretien au personnel qualifié. AVIS: Pour eviter les risques d'incendie ou d'électrocution, n'exposez pas cet article à la pluie ou a l'humidité. Either channel of the MX 3000a amplifier has special cliplimiting protection circuitry that reduces the signal level at the onset of heavy clipping. This not only allows the amplifier to operate at a high average power level without audible distortion occurring, but it also prevents the speakers' being destroyed by excessive clipping. However, if the amplifier is operating normally and your speakers fail anyway, it is virtually certain that they could not handle the high power, despite the lack of clipping. Even if you reduce the gain using the amplifier's front panel attenuator controls, it is still possible to reach full output power if the input signal level is high enough. VORSICHT GEFAHR EINES ELEKTRISCHEN SCHLAGES. NICHT ÖFFNEN! VORSICHT: Um das Risiko eines elektrischen Schlages zu vermindern, Abdeckung nicht entfernen! Keine Benutzer Wartungsteile im Innern. Wartung nur durch qualifiertes Wartungspersonal. WARNUNG: Zur vermeidung von Feuer oder elektrischen Schlägen, das Gerät nicht mit Regen oder Feuchtigkeit in Berührung bringen! A single high-power crescendo can blow high-frequency drivers almost instantaneously, while low-frequency drivers can usually withstand very high, continuous power levels for a few seconds before they fail. Reduce power immediately if you hear any speaker "bottoming out"-- harsh pops or cracking distortion that indicate that the speaker voice coil or diaphragm is striking the magnet assembly. QSC recommends that you use amplifiers of this power range for more headroom (cleaner sound) rather than for increased volume. SPEAKER OUTPUT SHOCK HAZARD SAFEGUARDS Electrical energy can perform many useful functions. This unit has been engineered and manufactured to assure your personal safety. Improper use can result in potential electrical shock or fire hazards. In order not to defeat the safeguards, observe the following instructions for its installation, use and servicing. An MXa amplifier is capable of producing hazardous output voltages. To avoid electrical shock, do not touch any exposed speaker wiring while the amplifier is operating. RACK MOUNTING PRECAUTIONS In portable racks, to avoid damage to either the amplifier mounting ears or the mounting rails, support the amplifier at all four corners. Contact the QSC Customer Service Department to order rear support brackets. PRECAUTIONS L'énergie électrique peut remplir de nombreuses fonctions utiles. Cet appariel a été conçu et réalisé pour assurer une sécurité personnelle entiére. Une utilisation impropre peut entraîner des risques d'électrocution ou d'incendie. Dans le but de ne pas rendre inutiles les mesures de sécurité, bien observer les instructions suivantes pour l'installation, l'utilisation et l'entretien de l'appareil. 3 II. OVERALL DESCRIPTION The MXa Series from QSC comprises four high-efficiency professional power amplifier models, each with two independent channels. The MX 1000a, MX 1500a, and MX 2000a, can deliver, respectively, 275, 400, and 475 watts into 8-ohm loads, and 400, 600, and 725 watts into 4-ohm loads Either channel of the MX 3000a is capable of delivering 850 watts into 8-ohm loads, 1300 watts into 4-ohm loads, or more than 1600 watts into 2 ohms. Each channel has its own transformer secondary (MX 1000a and MX 1500a) or power transformer (MX 2000a and MX 3000a) and bipolar multi-rail power supply. The power transformers are mounted in the front of the amplifier chassis, as close to the front mounting rails as possible; this keeps the unit's center of gravity forward to minimize the twisting force on the front mounting ears. Still, the amplifier should be supported at all four corners, especially if it is in a portable rack such as in touring or mobile applications. The MX 1000a and MX 1500a are both two rack spaces high and weigh 19 kg (42 lb). The MX 2000a and MX 3000a occupy three rack spaces. The MX 2000a weighs 24.5 kg (54 lb), and the MX 3000a weighs 31 kg (69 lb). The amplifiers require a rack depth of 18 inches (45.7 cm) to clear the rear support ears. Allow some additional clearance for input and output connectors at the rear panel, which is 16.9 inches (42.9 cm) behind the plane of the front mounting rails. The built-in cooling fan draws air in at the rear of the chassis and exhausts it through vents in the front panel. The flow-through cooling scheme allows you to rack-mount the amplifiers one atop the other, with no clearance necessary in between. This mounting technique also helps support the weight of the upper amplifiers. The MXa Series derives much of its design from our highend EX Series amplifiers. They are engineered for stability and exceptional reliability, with protection for open or short circuits and mismatched loads. To protect your loudspeakers, the outputs mute during turn-on and turnoff, and also in the event of a DC fault. All protection circuitry automatically resets to normal when conditions assure safe operation. The amplifiers feature thermal protection. The MX 3000a features a variable-speed fan, which responds continuously to the cooling needs to minimize noise and dust build-up, and a thermal limiter that reduces gain up to 15 dB if the amplifier overheats above 80° C. The other models have a two-speed fan. If an MXa amplifier overheats to 85° C or higher, a protection circuit mutes the output. ON PROT CLIP SIG PWR 14 18 24 GAIN 1 12 10 8 6 4 2 - dB GAIN 2 12 10 14 18 24 - dB 8 6 4 2 0 PWR SIG CLIP PROT MX 1500a Professional Stereo Amplifier OFF 0 Figure 1: QSC MX 1500a Front Panel (identical to the MX 1000a) ON PROT CLIP SIG PWR 14 18 GAIN 1 12 10 8 6 4 2 - dB GAIN 2 12 10 14 18 24 - dB 8 6 4 2 0 PWR SIG CLIP PROT MX 2000a Dual Monaural Amplifier OFF 24 0 Figure 2: QSC MX 2000a Front Panel (identical to the MX 3000a) 4 III. INPUTS An MXa amplifier features balanced inputs, connected via barrier strip terminals or 1/4" (6.3 mm) tip/ring/sleeve phone jacks. The tip of the input jack is wired for "negative' or inverted polarity, while the ring is the non-inverting input. Thus, if the voltage at the tip is positive with respect to that at the ring, the amplifier channel will produce a negative voltage at its output. For use with unbalanced signals, connect the unused terminal to ground to avoid a reduction in gain caused by a floating input; use a two-conductor (tip/sleeve) plug, or connect a jumper between the inverting input terminals on the barrier strip and their adjacent ground terminal. MX 1500a INPUTS The amplifier's input sensitivity is 1.07 volt rms; at this signal level and any attenuators set for full gain, the amplifier will produce full rated power--350 watts, 20Hz20kHz, 0.1% THD--into an 8-ohm load. The input impedance is 20 kilohm balanced and 10 kilohm unbalanced, typical of QSC amplifiers. MX 2000a INPUTS The amplifier's input sensitivity is 1.05 volt rms; at this signal level and any attenuators set for full gain, the amplifier will produce full rated power--450 watts, 20Hz20kHz, 0.1% THD--into an 8-ohm load. The input impedance is 20 kilohm balanced and 10 kilohm unbalanced, typical of QSC amplifiers. MX 1000a INPUTS The amplifier's input sensitivity is 1.1 volt rms; at this signal level and input attenuators set for full gain, the amplifier will produce full rated power--250 watts, 20Hz20kHz, 0.1% THD--into an 8-ohm load. The input impedance is 20 kilohm balanced and 10 kilohm unbalanced, typical of QSC amplifiers. MX 3000a INPUTS The amplifier's input sensitivity is 1 volt rms; at this signal level and any attenuators set for full gain, the amplifier will produce full rated power--800 watts, 20Hz-20kHz, 0.1% THD--into an 8-ohm load. The input impedance is 20 kilohm balanced and 10 kilohm unbalanced, t ...