levels occur Then, as temperatures in the amplifier heat sinks increase, the automatic thermal-sensing
circuitry will cause high-speed operation to occur. Depending upon signal conditions and amp loading,
high-speed fan operation may continue or the fan may cycle continuously between high and low. This
situation is quite normal. If cooling is inadequate, however, the amplifier thermal-sensing system may
cause temporary shut down of the unit, indicated by the LEDs on both channels going dark. Inadequate
cooling may be due to preheated air, reduces air flow resulting from blockage of inlet/outlet ports, severe
amplifier overload, or short circuit conditions. Depending upon the available cooling air, operation should
be restored relatively quickly, and the power LED on both channels will again be illuminated. In any
event, action should be taken to correct the cause of the thermal shutdown. If the amplifier is not severely
overloaded or shorted and air flow is normal in and out of the amplifier, then steps should be taken to
provide a cooler environment for all the amplifiers. As a general rule, the cooler electronic equipment
is operated, the longer its useful service life.
In most low to medium-power applications, the amplifier can be mounted in any configuration. It is
desirable that, if at all possible, the power amplifier be located at the top of an equipment stack. This will
prevent possible overheating of sensitive equipment by the hot air rising from the power amplifier. As a
general rule, most home and studio requirements will never cause high-speed fan operation. High-speed
operation may indicate that you have not taken the necessary steps to provide adequate cooling. Fully
closed up in a cabinet, a power amplifier will have severe cooling problems, even at low power levels.
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