To significantly increase the reliability of an amp, you can try using a fan cooling to force air through the fins of an amp’s heat sink. It is most effective especially for amp in restricted area like the under a seat mounted amp.
To install only one fan on the amp, you have to make sure it forces the air through the heat sink’s fins because the semiconductors are mounted to the heat sink. Sometimes people cut a hole in the amp’s bottom side to blow air onto the circuit board. If that is the only fan, it wont do very good.
If you have one fan blowing on the heat sink’s fins and you want to mount another fan blowing inside the amp, that will keep the transformer and large filter caps cool. But it is unlikely necessary unless you are going to use the amp for a long periods f time.
If the amp already has a built in fan, you have to make sure the new added fan wont interfere the built in fan. As an example, don’t try to force air into the exhaust of the fan cooled amp. Also if the amp has a built in fan, don’t make a new openings on the amp’s case because it can affect the amp’s cooling.
