CD Player/Transport Reviews

Sony's first CD player, the much-maligned CDP-1 (reviewed in Vol.5 No.10), did all the things we'd been promised from CD except deliver perfect sound. It met CD's incredible claims for frequency range and linearity, harmonic and intermodulation distortion, and signal/noise ratio, yet—despite my own initial enthusiasm for it—it proved ultimately to be a disappointing-sounding player (footnote 1). Its sound was rather hard and grainy, and quite spectacularly uninvolving to listen to. But considering that it was the first of its kind, it was a good start despite its many sonic shortcomings (footnote 2).

High-end manufacturers, however, were so disconcerted by the initial hostility of their market to CD that they initially stayed away from it, for fear of being tarnished by its unsavory reputation. After all, everyone assured one another, vinyl would still be around for ten years or so. Well, it wasn't to be. The entire industry was shocked at how quickly record stores ditched their entire inventories of LPs and replaced them with CDs. By 1990, the LP was dead and practically buried.

I'm not sure which was the first high-end manufacturer to take the plunge, but for the record, the California Audio Labs Tempest and PS Audio CD-1A were the first players from small American firms to be reviewed in Stereophile, three years after our CDP-101 review. The dam was broken—the deluge brought with it unprecedentedly detailed scrutiny of CD's shortcomings and an explosion of technological refinements that must have surprised even CD's inventors. Ever since, the CD majors have been working furiously to stay abreast of the advances. And although the highest-priced player/decoder combinations are still judged to be the top of the sonic heap, Tom Norton's early-1991 review of Sony's previous flagship model, the CDP-X77ES (Vol.14 No.1), compared it favorably with more modestly priced separates.

Like all of Sony's top-line products, the CDP-X799ES is loaded with bells and whistles, most of which—like Custom File and Shuffle Play—are of little interest to serious audio types. However, unlike the typical feature-laden product, in which performance is heavily compromised to keep the price competitive, the 779 gives every indication of real attention to quality. It's built like the proverbial brick outhouse, with a heavy, low-resonance chassis, a hefty power-transformer case (which apparently houses two transformers), and so on. The deck is solidly built and sounds that way, being reassuringly smooth and quiet in operation. It maketh no clunks, no bangs, no grinding-gear noises when the door opens and closes.

Design features
Most of the 779's basic design is the same as that of the earlier CDP-X77ES, to which review I refer interested readers. So I won't go into a long and tedious description of the 799ES's circuitry, chip sets, and interior decor. Rather, I'll mention only the features Sony felt were important enough to cover in a technical white paper about their 1992 players. (Yes, the 779 is that old.)

Complementary PLM A/D Converter: Instead of the X77's two DACs per channel, the 779's "high-density linear converter" uses four per channel to output its pulse-length–modulated (PLM) bitstream at 90 million pulses per second (footnote 3). This is claimed to provide even higher waveform precision than before and, as a side effect, an incredible 131dB S/N ratio!

Direct Digital Synchronization: Sony's attack on the jitter problem involves introducing the clock signal right into the DAC, at the point where the digital signal is converted to analog.

DC Servo FET Line Drive: The analog section in each channel consists of a servo-controlled, DC-coupled FET, with no capacitors whatsoever in the signal path. This addresses what has been shown to be the major shortcoming of most CD players: a mediocre analog section. The "servo" control is simply to ensure that no DC offset can appear at the output. I've always had a weakness for FET sound, particularly in low-level circuits, because it combines the best aspects of tube and transistor sound, with none of the shortcomings of either. The benefits of a capacitorless signal chain are unarguable.

Digital Servo: This refers to the servo that controls the player's laser-optical pickup. Long considered legendary in the disc-tracking department, Sony's players haven't seemed to need "improving" in that respect for a number of years, so this latest innovation would seem to be just icing on the cake. First used on laserdisc players, where tracking problems are exacerbated by the disc's 12" diameter, digital servo control simply means the analog output from the pickup is converted immediately to digital, kept in that form to do the necessary filtering (of noise and disc eccentricities) and control-voltage calculations, and then D/A'd just before feeding the servo control amplifiers.

Laserdisc players with digital tracking control have proven to be much more stable and glitch-free than with analog control, both in sound and picture, so there's no reason to believe CDs wouldn't be similarly helped. Whether the difference would ever be audible from CD is moot. But then, Sony's high-end players have always been designed with the view that "If it might conceivably help, why not do it?" (In high-end, we call this "no-holds-barred.") Because digital control-signal processing consumes less current with less current-drain fluctuation than analog processing, it should cause less signal-modulating power-supply voltage change in other parts of the player.

Solid Deck Platform: New materials and even heavier construction than in previous models reduce even more any tendency for the deck as a whole to resonate in response to rapid servo movements, for more precise and stable pickup positioning.

Improved Drive Motor: The turntable motor is a brushless, slotless (no large gaps between rotor segments) design to minimize cogging, and the bearing is a polished sapphire. (When, I wonder, will we see a vacuum-holddown CD platter?)

Sealed Disc Drawer: Not a new Sony feature—both Nakamichi and Meridian have transports and players with a sealed disc section—the drawer assembly is fitted with an air seal which, when closed, is supposed to prevent airborne sounds from impinging on the disc surface. Well, if that can foul an LP's sound, I suppose it could affect a CD. Everything else seems to.

Circuit Isolation: As much as possible of the wiring is now on rigid, low-resonance circuit boards, all of which are electrically isolated from one another for minimal noise leakthrough. Separate, shock-mounted twin-core power transformers serve the digital servo and signal-handling sections. There is only one AC cord. (Sony, you disappoint me!)

Me & CD Players
A word about me and CD players: Although I realize that musicality is the driving force behind subjective audio magazines like Stereophile, I am acutely nervous about using it as the sole criterion for judging any kind of record player, analog or digital. There is no objective measurement for musicality; it is necessarily a judgment call, and a very personal one at that. Since no reproduction really sounds like the real thing, a verdict of musicality depends on certain sonic cues which evoke in the listener memories of live concerts previously heard. When this happens, the mind fills in what's missing and the whole thing sounds real. Since different people pay attention to different aspects of sound, the things required to evoke that illusion of reality differ from one listener to another; what sounds musical to one may not to another.

The issue is further complicated by the critical listener's natural tendency to assume, because his reference system sounds neutral and free from colorations, that the individual components comprising it are equally neutral. He knows, deep down, that this is highly improbable, yet when he substitutes another component that makes the system sound less musical, there is a powerful temptation to see this as a failing of that new component, without even considering the possibility that his reference component may have been, for instance, complementing a coloration in his speakers that the new, intrinsically more neutral one doesn't.

Then there's the question of program material. Even if the listener actually made the recording he's listening to, he doesn't really know what it sounds like. Microphones don't hear sounds the way our ears do, and there's no way of listening to a recording except through a system which is itself almost certainly colored in ways we may not know about. The fact that the reproduction may sound like what is remembered of the real thing can give some reassurance that we're on the right track, but for all of the above reasons, I think it presumptuous of critics to base their opinions of a product entirely on how it makes things sound in their own systems.

But "presumptuous" is not how I feel about "comparing" a CD with its LP release; I think that is absurd. Colorations in CD players are trivial when compared with such differences between cartridges, arms, turntables, and preamps. The wholly unpredictable result of analog's mix'n'match roulette is hardly a reliable comparison signal, let alone a reference standard. An analog front end can be a fairly solid reference source if it has proven itself capable of making a large selection of well-made LPs sound like their original tapes, but few audiophiles have access to any original tapes, and even fewer who do have them have ever tried seriously to assemble LP players that sound like them.

So as far as I'm concerned, the function of a CD player is not to make musically pleasing (or even realistic) sounds, but to replicate the sound of the CDs' original master tapes. Period. If it succeeds in doing that, but doesn't sound "good" through the reproducing system, then either the original recording was poor or the playback system needs work. (There's also the possibility that the original may have suffered some loss in transfer to CD, but that happens less and less these days.)

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Footnote 1: Some criticisms of CD made at that time were wrong, however, such as the common assertion that a digital system with 44.1kHz sampling cannot reproduce a 20kHz sinewave. It's true, of course, that the best it can do is take slightly more than two samples of each 20kHz cycle, which logic tells us would cause truly prodigious distortion. But...the lowest (2nd) harmonic of 20kHz is 40kHz, and the very sharp output filter on all CD players eliminates any 40kHz signal, as well as all harmonics above it. And, by definition, a fundamental without harmonics is a pure sinewave.

Footnote 2: Edison's early phonographic efforts weren't all that great either, even though his promotions touted their sound as "just like being there." (At least he had the restraint not to tack "forever" at the end of it.) Analog audio's "legendary" quality and musicality, which we smugly hold up as proof of digital's wrongheadedness, took 116 years to develop. We're only 11 years into consumer digital.

Footnote 3: Long "pulses" are made up of a continuous series of short ones; the shorter the short ones—that is, the more of them per second—the smaller the amplitude steps that can be PWM-encoded; or, as Sony puts it, the higher the resolution. But like S/N ratio, the ultimate resolution of any CD player is system-limited—in this case, to 65,536 discrete amplitude levels.