Our feature story on the hum problems introduced into hifi
systems by DVD players with switchmode supplies and double-insulation
(SILICON CHIP, October 2007) prompted the
question: are CD players likely to produce the same signal-to-noise degradation
in high-fidelity amplifiers? After all, what is the point in paying top dollar
for premium hifi components which you expect to be utterly quiet, only to have
them produce low level hum and buzz?
The Denon DCD-700AE CD player is well made and uses a conventional linear power supply. The PC board at rear right carries the audio output filter which completely eliminates sampling artefacts.
The answer is that, unless the CD player in question has a
conventional transformer driven supply, the hum and buzz problems will be
exactly the same as for DVD players.
There are two ways around this problem. The first is to use the
digital optical output of your DVD or CD player in conjunction with the optical
decoder in your home theatre receiver. If you take that approach, you would want
to be sure that the digital decoder in your home-theatre receiver is at least as
good as the decoder in the player. If not, the sound quality will not be as good
as it potentially should be. In our experience, unless the home-theatre receiver
is a top-end unit, with a price to match, its decoder and general performance
are likely to be fairly ordinary.
The second approach is to purchase a high-quality CD player
with a conventional linear power supplier, such as this Denon CD player. Which
is how we came to be reviewing this particular machine.