QSC Audio MX2000a II. Overall Description, QSC MX 1500a Front Panel identical to the MX 1000a

II. OVERALL DESCRIPTION

The MXa Series from QSC comprises four high-effi- ciency 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 high- end EX Series amplifiers. They are engineered for stabil- ity and exceptional reliability, with protection for open or short circuits and mismatched loads. To protect your loudspeakers, the outputs mute during turn-on and turn- off, 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 continu- ously 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 over- heats to 85˚ C or higher, a protection circuit mutes the output.

ON			GAIN 1			GAIN 2
			12	10	8	12	10	8
PROT CLIP	SIG	PWR							PWR	SIG	CLIP	PROT
			14		6	14			6
			18		4	18			4
OFF			24		2	24			2
				- dB	0		- dB	0
MX 1500a
Professional Stereo Amplifier

Figure 1: QSC MX 1500a Front Panel (identical to the MX 1000a)

	ON			GAIN 1			GAIN 2
	PROT CLIP	SIG	PWR	12	10	8	12	10	8	PWR	SIG	CLIP	PROT
			14			6	14			6
			18			4	18			4
	OFF		24			2	24			2
MX 2000a						0			0
					- dB			- dB
Dual Monaural Amplifier

Figure 2: QSC MX 2000a Front Panel (identical to the MX 3000a)

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