Digital Amplifiers
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.
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