Analog music signals have been electronically amplified since the development of the first electrical phonograph in 1925. Originally amplifiers employed vacuum tubes to boost the analog signal to an amplitude (voltage) that could move a loudspeaker cone. A much more recent development was the use of transistors to amplify these tiny signals. Both of these technologies are relatively inefficient and produce heat as a by- product of their design. In order to mass- produce analog amplifiers at a reasonable cost the tolerances of the parts employed are reduced. This results in an increase in signal distortion and degradation and a loss in quality.
The distribution of Digital Audio on CD’s removed a very weak link in the audio signal chain and brought the quality of studio master tapes to the home. However the tiny audio signals produced by the DAC (Digital to Analog Converters) in the CD Player were still fed into an analog amplifier in order to be heard.
Now a revolutionary new technology called digital amplifier has come to the audio universe. Digital amplifiers make it possible for the audio signal to stay in its pure digital form through the complete audio signal chain to greatly enhance sound quality. In a pure digital amplifier, (one with a digital input ), there is no need for Digital to Analog Converters in the audio signal path. Digital Amplifiers actually synthesize the desired output signal directly on the speaker terminals, thereby creating a high-powered digital-to-analog converter.
Until very recently, the fully digital amplifier was only possible in laboratories, or in extremely expensive high-end audio systems. Now the technology has been reduced to just one or two chips, dramatically lowering manufacturing costs. In many cases this superior new technology can be incorporated into products even more inexpensively than the archaic linear audio amplifiers that will soon be known as “things of the past.”
In case we haven’t made ourselves perfectly clear, beware of digital amplifiers that only have analog inputs! These products are actually hybrids and are NOT pure digital.