California Audio Labs DX-1 CD-player Review

Although possibly not a household name, California Audio Labs, or CAL, is well known to audiophiles as a manufacturer of high-quality digital audio equipment and as the first to make a CD player with a vacuum-tube analog output section. The new DX-1 is a fully solid-state design, however, and the company’s lowest-price CD player to date.

Outwardly, the DX-1 is a pleasing departure from earlier CAL designs, which tended toward the stodgy. Its low-slung chassis and black plastic front panel give it a very contemporary, European look and will particularly appeal to those enamored of bilateral symmetry. The disc-loading drawer is in the middle of the panel, with a green liquid-crystal display (LCD) directly below it. The display’s vocabulary is limited to the basics: track number, track time, a sixteen-position track calendar, and notations for random, programmed, repeat, and mu-sic-scan playback. A remote sensor is nestled beside the display. Some users may find the display somewhat dim and illegible. On the other hand, those who dislike obtrusive displays will be happy to learn that this one’s backlighting can be turned off from the remote control. (Some people insist on turning them off because they think such displays contribute distortion to the audio signal, but it’s my humble opinion that these people are missing a few fries from their Happy Meals.)

There are three buttons on either side of the display for drawer open/close, play, pause, stop, previous track, and next track. A power button completes the front-panel complement. The player’s more advanced features are accessible only from the remote control. Its twenty-eight buttons duplicate the principal front-panel controls while adding two-speed forward and reverse search (audio level is reduced by 12 dB), random track playback, disc repeat, music scan (plays the first 15 seconds of each track), display selection for elapsed or remaining time in a track or total time remaining on the disc, twenty-track programming, and a twelve-key numeric keypad for direct track access and track-sequence programming.

The rear of the chassis is occupied with phono jacks for left and right analog signal outputs and a single digital output, which can be used with a 75-ohm coaxial interconnect cable (not supplied) to attach the DX-1 to a digital recorder or an outboard digital processor or digital-to-analog (D/A) converter. (Common audio cables should not be used for such a connection.) The DX-1 does not have an optical digital output, which is unfortunate because so many digital inputs on equipment these days are optical only. Finally, there is an IEC-type detachable AC cord with a three-prong plug. Fit and finish of the product are very good throughout.

The owner’s manual is thorough and mainly helpful. For example, it reminds you that if you elect to keep the DX-1 (or any audio component) powered at all times, it is particularly important to invest in a good surge and spike suppressor and to unplug the equipment when atmospheric conditions become threatening. On the other hand, it also recommends that the laser lens be cleaned periodically with “appropriate user-application kits.” I vigorously question the risk/reward ratio of such a practice.

The DX-1 is very Spartan inside its steel chassis, with only a fraction of the interior volume actually occupied, but there are many unusual design details sprinkled throughout. The disc transport is a linear worm-drive design (as opposed to the radial swing arm used in some players). It employs a single-beam laser pickup and digitally controlled servos for maintaining tracking, focusing, and rotational speed. Although made mainly of plastic, the transport's critical head section is die-cast, and overall it is well built and appears quite sturdy. In addition, whereas the lenses in most CD laser pickups are made of plastic, the DX-l's is made of glass. CAL’s faith in the device is such that it is used in all of the company’s players and transports.

The D/A converter used in the DX-1 is made for CAL by Matsushita—a sigma-delta (1-bit) design with 16-bit resolution. Unique in our experience, the converter is mounted on a circuit board that is attached to the disc transport itself. CAL says that this decreases the signal path between drive and converter, hence reducing interference and jitter. That may be true with respect to the digital signal path, but it lengthens the analog signal path; in particular, both audio channels must pass through a thin, flexible ribbon cable that electrically connects the transport to the main circuit board. Thus, at the very least, the CAL design is not completely free of compromise.

The main circuit board contains a single large surface-mount chip, which probably handles the player’s digital control systems, and also the power-supply and audio-output stages. There is an EMI (electromagnetic interference) line filter on the AC input line; its inductor and capacitors help eliminate noise from the AC power line. Right nearby is the power supply, with a resin-potted and shielded transformer that is said to generate less electromagnetic interference than standard transformers. When the DX-1 is turned on, its analog and digital outputs are muted for 13 seconds while internal components reach stable operating voltages.

CAL says that the audio signal is equalized to simulate the frequency response of a moving-coil phono cartridge, which is said to impart an “analog-like sound.” The analog output stage employs FET integrated-circuit (IC) op amps and a downstream discrete-component signal path with 1-percent-tolerance metal-film resistors and high-quality capacitors. Examination of the underside of the main circuit board reveals that even electrical engineers can have a sense of humor: There, etched in copper amidst a maze of traces, is “Where’s Waldo?”—the modem equivalent of “Kilroy Was Here.”

The DX-1 enjoyed smooth sailing on the test bench. Its frequency response was extremely flat (much flatter than that of any moving-coil cartridge we know of, by the way), channel separation exceeded 70 dB across the audio band, and both noise and distortion were very low. Maximum interchannel phase error was a negligible 3.4 degrees, but if you’re really desperate for something to worry about, that is slightly higher than usual. Much more important was the converter’s excellent low-level linearity. Perhaps most impressive, however, was the tracking performance of the laser pickup: It was able to negotiate the 4,000-micrometer defect on my Pierre Verany #2 test disc—the most extreme defect available on the disc. Only once before have I seen a player execute that feat. If you buy your audio equipment by the numbers, the DX-1’s suggest that you should reach for your wallet.

Most of us like to listen first, though. The differences in sound quality between good CD players are infinitesimally small compared with those between such components as tuners, equalizers, ambience processors, microphones, headphones, and loudspeakers, not to mention listening rooms, listening positions, and even haircuts (hair over the ears reduces high-frequency response). Still, even though many CD players are sonically indistinguishable from one another, there is no question that, for whatever particular reason in each case, some players do sound very slightly different from some others.

I auditioned the DX-1 over a period of weeks, feeding it a steady stream of new Mobile Fidelity discs, including remastered albums by such diverse performers as Muddy Waters, Heart, and Todd Rundgren. These discs put the DX-1 through its paces, testing aspects such as transient distortion, transparency, and soundstage. I listened for solid bass response that delivered a pounding to the speakers but was never boomy. I listened for a transparent midrange that was free of any noise and distortion at low signal levels. I listened for high-frequency response that was clear and open and never brittle. The DX-1 delivered in all categories to great effect. Any negative nuance that caught my attention could not be positively identified in subsequent listening sessions. Such inconsistency in fault-finding usually means that fantasy, not fact, is at play. The only consistency from one listening session to another was an impression of very, very solid audio performance.

Satisfied with the sound, I tried a number of very old, badly scratched discs; the transport faithfully played through these data minefields without complaint. Throughout the audition, I was impressed with the speed of the pickup, which responded exceptionally fast to track-access and search commands. Finally, I should note that the player was largely immune to impacts on its top and sides.

Although there is great economy in the design of the DX-1, the CAL engineers were careful to spend their budget where it was most needed and to refrain from wasting resources on less important aspects. Unlike reproduction of analog sources, a very fragile enterprise in which any lapse ruins the whole, digital reproduction is generally quite robust and enables considerable flexibility. In my opinion, the CAL designers have understood this characteristic perfectly and have exploited it to wring impressive performance from fairly modest parts.

In other words, the DX-1 is an example of what good engineering is all about. Almost any engineer can create an inefficient design that performs well and costs a lot, but only the genuinely talented can achieve great results at low cost. If you admire that kind of audio engineering, you’ll appreciate the California Audio Labs DX-1 player.

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