Owner’s Manual MXa Series ▲ MX 1000a ▲ MX 1500a ▲ MX 2000a ▲ MX 3000a ® A U D I O *TD-000026-00* Rev.
MXa Series Power Amplifier Operation Manual TA B L E O F C O N T E N T S I. WARNING NOTICES ................................................. 3 Speaker Damage ....................................................... 3 Speaker Output Shock Hazard .................................. 3 Rack Mounting Precaution ......................................... 3 II. OVERALL DESCRIPTION ........................................ 4 III. INPUTS ......................................................................
CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN 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. 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.
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.
MX 1500a INPUTS 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.
IV. OUTPUTS V. OPERATIONS Four “touch-proof” binding posts—one pair per channel—on the rear panel allow speaker cable connections to the amplifier outputs. The special design allows connection of large diameter speaker cable while reducing shock hazard due to the high output power of MXa amplifiers. The “hot” terminal of each output pair is the red one; the black one is signal ground.
TROUBLESHOOTING PROBLEM: Channel will not come out of muting • If reducing the gain control to ∞ attenuation does not release muting, the channel is defective or overheated (see “Overheating,” below). • If reducing the gain releases the muting, raise the gain back up slowly while you watch the “SIG” and “CLIP” indicators; the problem may be an abnormal signal (with excessive ultrasonic energy, for example) that could otherwise damage your speakers.
SPECIFICATIONS FTC Watts Per Channel 20Hz-20kHz, 0.1% THD MODEL 8Ω Load MX 1000a MX 1500a MX 2000a MX 3000a 250 350 450 800 4Ω Load EIA Watts Per Channel 1kHz, 1% THD 8Ω Load 350 500 650 1200 275 400 475 850 4Ω Load 2Ω Load* 400 600 725 1300 500 750 1000 1600 *typical Bridged Mono 20Hz-20kHz, 0.
MX 1000a MX 1500a MX 2000a MX 3000a CONNECTORS (each channel) Input: Output: Barrier strip and 1/4” RTS phone jack “Touch-Proof” binding posts COOLING MX 1000a, MX 1500a, MX 2000a: 2-speed fan with back-to-front air flow MX 3000a: Continuously variable speed fan, with back-to-front air flow AMPLIFIER PROTECTION Output Averaging™ short-circuit protection, open circuit, ultrasonic, RF, thermal muting (thermal limiting also on MX 3000a). Stable into reactive or mismatched loads.
PARALLEL, STEREO, OR BRIDGED OPERATION The Parallel-Stereo-Bridge switch is located on the input panel, next to the input jack for channel 1). The most commonly used operating mode for a power amplifier is “Stereo,” in which the two channels are independent and separate all the way from input to output. Set the switch in the center position for stereo operation. “Parallel” ties the two channel inputs together so that both will be driven by the same signal, without the need for external jumpers or wiring.
AC CURRENT CONSUMPTION VI. LONG-TERM OUTPUT POWER In a properly designed sound system, you can usually obtain the desired sound level without using the full output power of the amplifier; if the “CLIP” indicators flash once in a while, that is perfectly normal. If the amplifier is operated at extremely high power levels, it may overheat or may even damage the speakers. The amount of stress on the amplifier depends largely on the load and how hard the amplifier drives it.
HEAT EMISSIONS Essentially, a power amplifier draws electrical energy from the AC mains, converts it to DC, and then converts it again into an analog of the input signal to send out to the loudspeakers. Any AC power that enters the amplifier through the power cord and does not exit through the speaker outputs turns into heat, which the amplifier must rid itself of by exhausting it to the outside. In indoor use this may present a sizeable challenge to a building’s air conditioning system.
output until it can be repaired, at which time the fuse should be replaced also. Temperature sensors on the channel heatsinks and the power transformers are part of the thermal management circuitry. On the MX 1000a, MX 1500a, and MX 2000a, the temperature sensors govern whether the dual-speed fan should run at low or high speed. Below 55˚ C, the fan runs at low speed; above, it runs at high speed. At or above 85˚ C, the channel mutes to go into thermal protection.
QUALIFIED SERVICE CENTERS QSC maintains a service center network for your convenience. If you choose to return your product to a local service center, you may call QSC Technical Services for a referral. Accessories, input modules and other peripheral QSC products must be returned to the factory for service. INTERNATIONAL SERVICING For QSC products that are purchased outside of the United States, service must be referred to the distributor or dealer from where the product was purchased.
X. IMPORTANT ADDRESS AND TELEPHONE INFORMATION Factory address: QSC Audio Products, Inc. 1675 MacArthur Boulevard Costa Mesa, California 92626-1468 USA Factory telephone numbers: Main Number (714) 754-6175 Sales Direct Line Sales (714) 957-7100 (800) 854-4079 (toll-free in U.S.A. only) Sales & Marketing FAX (714) 754-6174 Customer Service Customer Service (714) 957-7150 (800) 772-2834 (toll-free in U.S.A.
® A “QSC” is a registered trademark of QSC Audio Products, Inc. 16 U D I 1675 MacArthur Blvd.
