Latest models of audio amplifiers (http://www.amphony.com/products/audio-amplifier.htm prove that audio technology has gone the same course as computer technology and cell phones. While the features are growing, the size of today’s consumer products is becoming smaller and smaller. In the past, tube amps would be commonplace and take up a large part of the living room. Tube amps still have their fair share of fanatics. Nonetheless they have been replaced by solid-state amps for the most part.
Modern solid-state amplifiers combine the traditional pre amp and power amp stages into a neat single package no larger than a DVD player. New developments in audio technology in regard to power efficiency of have allowed the development of a new generation of super-miniature audio amplifiers, such as Amphony’s microFidelity Model 200. These mini amps take up no more space than a deck of cards but deliver up to 50 Watts, which is enough to drive a speaker to high volume.
“Class-A” and “Class-AB” amplifier topologies were the two major amplifier architectures of previous audio amplifiers. These technologies have fairly low power efficiency. Only a small percentage of the consumed energy – typically in the order of 20% to 30% – is actually converted into audio by analog amplifiers. The left over portion is radiated as heat. Analog amplifiers therefore require significant cooling which is done by heat sinks that are often bulky and prevent the amplifier from being made very small.
“Class-D” amplifiers are based on a digital design which provides larger power efficiency than “Class-A” or “Class-AB” amplifiers – normally in the order of 80% to 95%. Consequently only a small portion is wasted as heat which was the key in being able to miniaturize audio amplifier designs. One main drawback of “Class-D” amplifiers is the fact that digital “Class-D” amplifiers use a switching stage at the output which creates non-linearity and therefore some amount of distortion of the audio signal. This downside has slowed the advance of digital amplifiers.
More recent “Class-T” and newer “Class-D” amplifier product types, such as Amphony’s Model 200, incorporate a feedback mechanism where the output of the amplifier is fed back to the input. This feedback allows the amplifier to compensate for nonlinearities of the output switching stage and consequently lower audio distortion to similar levels of analog amplifiers whilst preserving the audio efficiency of digital amplifiers.
These new generation miniature audio amplifiers are suited for a range of new applications where previous audio amplifiers have failed. These applications include installations, such as in-ceiling installations, with minimum space or connecting speakers to a cable box or DVD/MP3 player where minimum space is key.