Are Miniature Power Amplifiers A Match For Big Amplifiers?
New generation amplifier models are a result of the same miniaturization that has caused computers and cell phones to shrink. While the features are growing, the size of today’s consumer products is getting 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 Nonetheless they have been replaced by solid-state amps for the most part.
While traditionally there would be separate pre amp and power amp stages, today’s solid-state amp combine everything into a neat box no larger than the size of a VCR. A new generation of super-miniature amplifiers, such as the Amphony Model 200 microFidelity amp, has become feasible due to new developments in audio technology regarding power efficiency. These mini amps take up no more room than a deck of cards but deliver up to 50 Watts, which is enough to drive a speaker to high volume.
In history, audio amplifiers would possess comparatively low power efficiency due to the “Class-A” and “Class-AB” architecture of analog amplifiers. Only a small portion of the consumed energy – typically in the order of 20% to 30% – is actually converted into audio by analog amplifiers. The remaining portion is radiated as heat. Therefore analog amplifiers require a reasonable amount of cooling. The amount of cooling depends on the amplifier rated output power. These heat sinks prevent the amplifier to be built into a small form factor.
Digital “Class-D” amplifiers offer higher power efficiency than analog amplifiers – typically around 80% to 95% – and thus can be miniaturized. One main drawback of “Class-D” amplifiers is the fact that digital “Class-D” amplifiers use a switching stage at the output which causes non-linearity and thus some amount of distortion of the audio signal. This drawback has slowed the advance of digital amplifiers.
Some new amplifier brands have emerged. Among those are “Class-T” and newer generation “Class-D” architectures. These types of new architectures, such as the technology used in Amphony’s Model 200 use a feedback mechanism. The output signal is fed back to the amplifier input. By using this feedback, the amplifier can compensate for nonlinearities of the output stage. This permits the distortion to be reduced to levels similar to analog audio amplifiers. At the same time the amplifier provides the high power efficiency of digital amplifiers.
These new miniature audio amplifiers open up applications where traditional amplifiers have failed. They are suited in particular for installations with minimum space, such as in ceiling speakers. Other applications include connecting speakers to a DVD/MP3 player or cable box.
You can find additional information about power amplifier products as well as other amplifier product models from Amphony’s web site.
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