MACKIE M1400/M1400i - Manual (Page 23)

23
GENERAL PRECAUTIONS AND CONSIDERATIONS
AC POWER CONSIDERATIONS
Be sure the M•1400/M•1400i is plugged into
an outlet that is able to supply the correct volt-
age specified for your model.
If the line voltage should drop below about
97% of the rated voltage, the M•1400/M•1400i
will no longer be able to supply rated power. (It
will continue to operate down to 50% of the
rated line voltage, but it just won’t be able to
reach full rated power.)
Be sure the AC outlet can supply enough
current to allow full power operation of all the
amplifiers plugged into it. The outlet should be
a socket that matches the power cord.
WARNING: Bypassing the plug’s ground pin
can be dangerous. Don’t do it!
The AC current demand of an amplifier var-
ies depending on several factors, including the
crest factor and the duty cycle of the program
material. Under typical conditions reproducing
rock music where musical peaks are just below
clipping, the M•1400/M•1400i requires the fol-
lowing average currents:
RACK MOUNTING
The M•1400/M•1400i amp requires two
rack space units (2 IU = 3.5"). It also requires
16.25"(M•1400) or 16.38" (M•1400i) depth in-
side the rack, including the rear supports.
When designing your rack, put the heavier
items at the bottom and the lighter items to-
ward the top.
Secure the front panel of the amplifier to
the front of the rack using four screws with soft
washers to prevent scratching the panel. In ad-
dition, because of the weight of the amplifier,
you must secure the rear support brackets of
the amplifier to the back of the rack. You could
use a support rail or shelf across the back of
the rack, or angle brackets attached between
the rear support brackets and the rear rails of
the rack. This is recommended for all compo-
nents mounted in a rack that is going to be
moved frequently (or thrown in the back of a
pickup truck and transported down a bumpy
gravel road to that outdoor festival!).
THERMAL CONSIDERATIONS
The M•1400/M•1400i amp is fan-cooled and
brings air in through the front and out through
the sides. Make sure that cool air is available at
the front of the amplifier, and that there is
room on each side for the warm air to exit from
the amplifier and dissipate. If rack-mounted,
make sure there is room for the warm air to
circulate around the side and out through the
rear of the rack. In a typical rack, there will be
a space of 1 to 2 inches on either side of the
amplifier. This is adequate to allow the warm
air to exit from the amplifier.
The M•1400/M•1400i’s unique T-Design
Constant Gradient Cooling Tunnel provides
substantially better cooling for the output tran-
sistors than conventional designs that simply
blow air through the chassis, getting dust and
other contaminants over all the internal
components. The Cooling Tunnel provides a
shorter, more directed path so the cool air con-
centrates on the heat produced by the output
devices. This results in increased reliability
and longevity for the amplifier.
Average Peak
Current Current
Amplifier Loading Required Required
120V 240V 120V 240V
2 ohms per side or 4 ohms bridged 8A 4A 25A 12.5A
4 ohms per side or 8 ohms bridged 5A 2.5A 16A 8A
8 ohms per side or 16 ohms bridged 3.2A 1.6A 10A 5A
It is recommended that a stiff supply of AC
power be used because the amplifier places high
current demands on the AC line. The more power
that is available on the line, the louder the ampli-
fier will play and the more peak output power
will be available for cleaner, punchier bass.
Under typical conditions, reproducing rock
music where musical peaks are just below the
clipping point, you can safely connect more
than one amplifier to an AC service. Use the table
below as a guideline:
Maximum Number of Amplifiers
on a 120V/15A Service
Amplifier Loading (or 240V/7.5A Service)
2 ohms per side or 4 ohms bridged 2
4 ohms per side or 8 ohms bridged 3
8 ohms per side or 16 ohms bridged 5
Due to in-rush current, you should avoid
turning them all on at the same time. Rather,
sequence them on, one at a time, to prevent
popping the circuit breaker.