Power Amplifiers, Demystified by Your AV Professionals
published onDecember 20, 2012

As with most modern technology (just think of the iPhone!) power amplifiers have gotten slimmer and lighter in recent years. Previous models took up four rack spaces and weighed nearly 80 pounds. Comparable amps today take up a mere two rack spaces, weigh less than half the weight of previous models, and deliver more than twice the power. That’s not to mention all the onboard DSP, network control and remote monitoring now built in. Audio visual customers ranging from restaurant owners to night club designers will find all the power they need in amps that are more affordable than ever.

Amplifier technology is designated with different classes, from Class D to Crown’s proprietary Class I topology. Let’s take a quick look at some of the power amplifier options on the market today. For more details, check out the photo gallery at Pro Sound Web. (Besides, you’ve gotta love anyone who leads a tech article with a Star Trek quote.)

Class D amplifiers Transistors switch on and off using Pulse Width Modulation similar to digital sampling but in the analog realm.

Class G amplifiers The signal is switched between two power supplies depending on the output volume levels. The amp draws more power only when greater amplification is needed, saving energy, permitting the amplifier to run cooler and, ultimately, slightly reducing operating costs.

Class H amplifiers Like Class G amplifiers, these amps use two power supplies. The higher voltage power supply is variable based on the audio signal for greater energy efficiency.