Transformer at the power amp car serves to inverter voltage from 12 volts to symmetrical voltage B+, Ground, and B-. Large number of small output voltage specified email copper winding. This transformer produces a heavy burden on high heat. Sometimes a lot of disparaging the quality of copper used. In some cases the copper windings often found it burned so short with each other. This resulted in the breakdown FET transistors. Even a lot to burn and spread to the PCB. To increase the output power transformer can be modified by adding a winding in the output, so that the voltage increases and eventually the main amplifier needs to be stable.
To increase the life of the power amp should slow down users sounding audio, sometimes the user to force the audio as loud as possible without considering the level of heat generated. With normal use your power amp will be more longevity and of course the cost of servicing more suppressed.