How many watts do I need for my power supply?

It is possible to take a cost-effective approach to power amp design by reducing the size of the heat sinks on the output devices below that needed to avoid overheating on continuous sine wave drive at maximum output. Such an approach was once valid, as it recognised that fact that on 'real' recordings there is no need to provide for continuous full output as the gross distortion caused by clipping on brief peaks will result in the user turning down the volume before damage is done. On modern amplifiers it is possible to take such an approach without risk of damage, using integrated amplifier chips which tend to incorporate 'thermal protection'. However, the trend towards heavy compression and limiting on commercial recordings in recent years means that people expect to play these at high volume without clipping, and so the validity of the 'peak music power' approach to amplifier design has mostly been removed.