Crest Audio PRO 200 SERIES, Owner'S Manual

Page: 9 / 33

p. 5
Installation
2
Make certain that there
is enough space around
the front and rear of the
amplifier to allow the
heated air to escape.
When mounting in a rack,
try to avoid using doors
or covers on the front
and rear of the enclosure;
the exhaust air must not
be impeded
suggestion
In racks with closed backs
allow at least
one
stan-
dard-rack-space opening
for every four amps.
a
Cooling Requirements
Pro 200 Series amplifiers use a forced-air cooling system to maintain a low, even
operating temperature. Air is drawn into the amplifier by fans on the rear panel,
which passes over the cooling fins of the heat sinks and exhausts through the front
grille. If either heat sink gets too hot, its sensing circuit will open the output relay,
disconnecting the load from that particular channel. It is important to have an ade-
quate 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 unit is rack mounted, do not
use doors or covers on the front of the rack; the exhaust air must flow without
restriction. If you are using racks with closed backs, use fans on the rear rack panel
to pressurize the rack to ensure an ample air supply. Also make sure there is one
standard rack space opening for every three mounted power amplifiers.
Maintenance
Pro 200 Series amplifiers require little routine maintenance.
When used in an extremely dusty or smoky environment , it should be periodical-
ly blown free (using compressed air) of any foreign matter that may have built up
inside.
When used in an environment where residue from smoke/fog machines is regular-
ly present, the amplifier(s) should be periodically checked (by authorized Crest ser-
vice personnel) for build-up of that residue
Users will not need to make any adjustments to the amplifier during its lifetime.
There are no user-serviceable parts or adjustments that require opening the unit.
Additional Guidelines
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 in Chapter 5 for
more information on voltage.
Note — Always turn off and disconnect the amplifier from mains voltage before
making audio connections. As an extra precaution, have the attenuators turned
down during power-up.
Although Pro 200 Series amplifiers have AutoRamp circuitry, which raises the signal
level gradually after the output relay closes, it is always a good idea to have the gain
controls turned down during power-up. This will prevent speaker damage if there
is a high signal level at the inputs. Whether you buy or make them, use high quality
connections, input cables and speaker cables, along with a good soldering technique.
Most intermittent problems are caused by faulty cables.
Consult the the Wire Gauge Charts in Appendix C to determine proper gauges for
different load impedances and cable lengths. Cable resistance robs amplifier power
in two ways: power lost directly to resistance (I2R loss) and by lowering the total
load impedance. Also make sure the mode switch is set correctly for the desired
application. See Chapter 4 for more information on modes.