I'm a bit confused but perhaps what Audiozen is trying to say re voltage "fluctuations" is that in an unregulated power supply the voltage must drop significantly in order for the transformer to produce current. Load the amplifier further and the voltage will drop further and the transformer will deliver more current than its rated value, potentially overheating it?
Al has it right though. Power dissipation, however that happens, is the producer of heat. The Magtech runs cool because its transistors have an extremely linear transconductance function and therefore do not require much bias to eliminate crossover distortion. Most of the heat produced in a Class AB amp is produced by the bias current. The sole purpose of the bias current is to eliminate distortion. Through the use of linear Thermal Trak transistors very little bias current is needed to eliminate distortion and the amplifier as a result runs cool.
Al has it right though. Power dissipation, however that happens, is the producer of heat. The Magtech runs cool because its transistors have an extremely linear transconductance function and therefore do not require much bias to eliminate crossover distortion. Most of the heat produced in a Class AB amp is produced by the bias current. The sole purpose of the bias current is to eliminate distortion. Through the use of linear Thermal Trak transistors very little bias current is needed to eliminate distortion and the amplifier as a result runs cool.