A lot has changed in terms of the technology that is used in audio amplifiers over the years. Just a decade ago, tube amplifiers were commonplace. Also, the majority of amps would be bulky, easily run hot and consume lots of power. In contrast, modern amps have become very power efficient and small. In this article, I’ll describe how new technology has made this dramatic change possible.
While in the past, many people would purchase a separate preamplifier and main amplifier, nowadays, everything has shrunk enough to fit inside a single enclosure. Even though there are still fans which are fond of owning big tube amplifiers, the vast majority of people uses fairly small or even ultra-small amps. Some of these amps are no longer separate but are already integrated into other equipment. For example most AV receivers used for surround speakers integrate power amps for each channel. These receivers pack hundreds of watts into a small enclosure.
The main reason for amps becoming so small has been the introduction of Class-D amplifiers. These amps achieve an efficiency in the order of 90% while classic amps would have a power efficiency of less than 30% and therefore need heavy cooling fans and occupy a lot of space.