Crest Audio CPX 3800 owner manual Cooling requirements, Operating precautions

installation 2

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.

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.

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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 (I2R 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

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