Crest Audio CPX 3800 - Manual (Page 13)

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p. 13
installation
Make certain that there
is enough space around
the front and rear of the
amplifier to allow the
heated air to escape.
suggestion: In racks
with closed backs,
allow at least
one
standard-rack-space
opening for every
four mounted power
amplifiers.
a
cooling requirements
The CPX™ Series amplifiers use a forced-air cooling system to maintain a low, con-
sistent operating temperature. Air is drawn into the amplifier by fan(s) on the rear
panel, courses through the cooling fins of the tunnel-configured channel heat sink(s),
and then exhausts through the front panel grille. If either heat sink gets too hot, its
sensing circuit will open the output relay, disconnecting the load from that particular
channel. The CPX 3800 utilizes one common heat sink and a single fan, but retains
the separate circuitry. NOTE: Maintain an adequate air supply at the back of
the amplifier and enough space around the front of the amplifier to allow
the cooling air to escape. If the amp is rack mounted, do not use doors or covers
on the front of the rack; the exhaust air must flow without resistance. If you are using
racks with closed backs, use fans on the rear rack panel to pressurize the rack and
ensure an ample air supply.
operating precautions
Make sure the mains voltage is correct and the same as that printed on the rear of the
amplifier. Damage caused by connecting the amplifier to improper AC voltage is not
covered by any warranty. See the Connecting Power section for more information on
voltage requirements.
Although the CPX Series amplifiers have AUTORAMP ™ circuitry, which raises the
signal level gradually after the output relay closes, remember to have the gain controls
turned down during power-up to prevent speaker damage if there is a high signal level
at the inputs. Whether you buy or make them, use good-quality connections, input
cables and speaker cables, along with good soldering technique, to ensure trouble-free
operation. Most intermittent problems are caused by faulty cables.
Consult the Wire Gauge Chart to determine proper gauges for different load
impedances and cable lengths. Remember that cable resistance robs amplifier power
in two ways: power lost directly to resistance (I
2
R loss), and by increasing the total load
impedance, thereby decreasing the power demanded of the amplifier. Also, make sure
the mode switch is correctly set for the desired application. See Sections on Stereo,
Parallel and Bridged Mono modes for more information.
Always turn off and
disconnect the amplifier
from mains voltage
before making audio
connections. Also, as an
extra precaution, turn
the attenuators down
during power-up
a
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