QSC Audio MX 1000a - Manuel (Page 4)

4
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.
GAIN 2
PWR
24
18
14
12 10 8
6
4
2
0
- dB
SIG CLIP PROT
GAIN 1
24
18
14
12 10 8
6
4
2
0
- dB
PWR SIG CLIP PROT
Dual Monaural Amplifier
ON
OFF MX 2000a
Professional Stereo Amplifier
ON
OFF
GAIN 2
PWR
24
18
14
12 10 8
6
4
2
0
- dB MX 1500a
SIG CLIP PROT
GAIN 1
24
18
14
12 10 8
6
4
2
0
- dB
PWR SIG CLIP PROT
Figure 1: QSC MX 1500a Front Panel (identical to the MX 1000a)
Figure 2: QSC MX 2000a Front Panel (identical to the MX 3000a)