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.