Understanding Amplifier Power Ratings

by Pat Brown

This is a 5-part series discussing audio amplifier fundamentals and performance metrics.

The audio power amplifier is perhaps the most under-specified component in the signal chain, whose performance is often based only on a face value power rating. Is that really all there is to it? Are all “500 watt” amplifiers the same? In this series I will present some universal fundamentals concerning audio amplifier performance, concluding with a rating method that allows meaningful performance assessments and model-to-model comparisons.

Hint: Part 5 includes a brief overview of Parts 1-4. If you are in a hurry,  just skip to Part 5 to get the big picture.

Part 1 – What is Constant Voltage?


Part 2 – Limitations On Amplifier Current

Part 3 – Amplifier Test Waveforms

Part 4 – Amplifiers are for Loudspeakers – Loudspeaker Power Rating Types

Part 5 – The Power Rating Matrix

What’s Next?
In the coming weeks I will formally present a ratings matrix and freeware data viewer for the Common Amplifier Format. In the spirit of the Common Loudspeaker Format, the CAF provides a formal testing process for amplifiers,  and a concise presentation of amplifier specifications. It provides the necessary data to deploy and compare amplifiers of all types.  pb