Naim NA CDS CD player
Although George Bernard Shaw didn't have Naim Audio's founder Julian Vereker in mind when he wrote those words, they seem tailor-made for Julian's audio design style. Rather than make products that conform to what the rest of the audio world is doing, Julian builds them the way he thinks they should be. The result is often, shall we say, idiosyncratic.
Nothing exemplifies this thinking more than the Naim CDS (for Compact Disc System) CD player. Everything about the CDS's design, from its overall configuration down to its tiny disc-clamping mechanism, flies in the face of conventional wisdom about how digital front-ends should be built. The $7395 CDS is a study in optimizing the mechanical aspects of CD playback. Although the unit uses conventional electronics (4x-oversampling Philips chip set, op-ampbased analog output stage), the mechanical design is, to say the least, unconventional.
Like the Linn Karik/Numerik CD player that I reviewed in January, the Naim CDS is the first CD player from a UK company long known for its aversion to digital. Until recently, Naim preamplifiers had no input marked "CD," clearly a statement about how they felt about the virtues of analog. Now Naim has broken the digital barrier with their CDS.
Although the CDS is a two-box CD player, it isn't split along the usual transport/processor lines. Instead, the bottom box is the power supply and the top box contains the transport and digital-to-analog convertera CD player with an outboard power supply. A multi-pin cable connects the CDS power supply to the player. Both chassis are housed in Naim's standard extruded aluminum cases, and maintain the Naim look. In fact, the CDS power supply looks identical to both the NAP 250 power amplifier and NAC 52 preamp power supply.
The player's front panel contains a large and prominent green LED display (showing either track and index number or elapsed time) and six square pushbuttons. The latter duplicate many of the remote control's functions: Play, Stop, Next, Previous, Display, and Pause. The remote also has a keypad for directly entering specific track numbers, and repeat and programing features. The front-panel buttons and display are very large, easy to use and read, and the buttons are accompanied by back-lit displays indicating their functions.
The top-loading transport is accessed by a small smoked-plexiglass hinged cover that is flush with the chassis top. Opening the cover reveals a well containing the transport mechanism. When a CD is placed on the transport, a small clamp secures the disc to the spindle. After the lid is closed, the disc spins briefly, enabling the player to read the disc's table of contents. (If the lid is closed without the clamp in place, the disc flies off the spindle.) A safety interlock prevents the laser from turning on when the lid is open.
The CDS's power supplythe most massive I've seen in a CD player or D/A converter except for the Mark Levinson No.30is the size and weight of many power amplifiers. The analog supply starts with a 300VA toroidal transformer with two center-tapped secondary windings. The transformer secondaries are filtered by a pair of 15,000µF capacitors and rectified by two halves of two full-wave bridges. The analog supply output is then regulated to ±24V by a pair of TO-3 3-terminal regulators (footnote 1). The analog supply rails appear on the 13-pin rear-panel jack for connection to the player. Inside the player, the ±24V supply is re-regulated to ±18V.
The digital supply also uses a huge, dual-secondary toroidal transformer, with one secondary winding supplying the transport and servos and one supplying the digital electronics. The ±24V transport/servo supply and 13V digital supply are each filtered with a pair of 15,000µF caps and regulated with TO-3 regulators. In all, the power supply has six TO-3 regulators and an astonishing 90,000µF of filter capacitance. All this regulation is merely the first stage: these regulated supply rails are re-regulated inside the player by 19 TO-220 devices.
Footnote 1: The TO-3 is the round metal can that power transistors are often packaged in. This is a much beefier package than the more common TO-220 flat pack.