Linn Karik/Numerik CD player RH October 1994 page 2

Because of the rapid turning on and off of their transistors, switching supplies radiate high-frequency noise, some of which gets into and pollutes the adjacent audio circuits, which is one reason they generally haven't been used in audio components (footnote 2), [David Berning's amplifiers are the only high-profile designs to use switching supplies since the demise of the Infinity and Sony PWM amplifiers.—Ed.] Linn believes that they've overcome this limitation, claiming not only to have solved the radiated noise problem, but also suggesting that the new power supply "transforms" the musical performance of the products into which it's installed.

But enough technical minutiae. It's time to listen.

Music: As in my original review, I treated the Karik and Numerik as a CD player in two boxes. The separate clock line between the two that so improved the sound makes the use of these two components together a natural.

The Karik's and Numerik's output fed a Sonic Frontiers SFL-2 preamp, which drove Audio Research VT150 tubed monoblock amplifiers. Loudspeakers were Genesis II.5s, accompanied by the Genesis servo amplifier that drives the woofers. Loudspeaker cables were Transparent Ultra, and interconnects were Transparent and Magnan Type IIIi.

My first comparison was between the Numerik with the PCM63s and the unit retrofitted with the PCM1702s. Both had the conventional linear power supply. When I first listened to the original Numerik (PCM63), I was instantly reminded of why I'd so praised this processor in my original review. The Numerik had a distinctive sound that made music unfatiguing and easygoing; specifically, its perspective was smooth, gentle, and laid-back. The treble was extremely clean and free from glare and hash, and was well-integrated harmonically with the rest of the spectrum; I didn't experience the common digital phenomenon of hearing the treble as a separate, not quite integrated component of the music. Through the Numerik, the treble was a more natural part of the music's harmonic tapestry. One could, however, generally describe the Numerik as sounding slightly dark.

The bass was just as I remembered it: soft, not very extended, and a little woolly. This was my most salient criticism in the review, and one that hit home again after not hearing the Numerik for more than two and a half years. These characteristics prevented the Numerik from fully expressing the music's pace, drive, and bass dynamics and articulation (footnote 3).

With that re-orientation, I switched to the Numerik fitted with the 1702. The sound was very different. The characteristics that defined the original Numerik were largely changed—and not always for the better. First, the 1702 had a more forward, incisive, and immediate perspective. I wouldn't call the 1702-fitted Numerik vivid in relation to other digital processors, but the music was considerably more up-front than when interpreted by the PCM63 version. Further, the silky treble smoothness of the original Numerik was replaced with a brighter, less clean rendering through the 1702. The new DACs seemed to add a slight layer of hash and grain. The 1702-fitted Numerik wasn't bad, but the treble magic of the original Numerik was gone. Similarly, midrange textures were less liquid, instead taking on a slightly harder edge.

On the plus side, the 1702-fitted Numerik had much better bass. Articulation—the ability to hear pitch, detail, and dynamics—was significantly improved. The stunning bass playing on John McLaughlin's Qué Alegría (Verve 837 280-2) was much easier to hear, and the bass balance as exemplified by that recording was leaner, tighter, less woolly—a welcome change. Bass extension was also improved, giving kickdrum more weight and impact. The tremendous sense of pace and rhythm on Robben Ford and the Blue Line (Stretch STD 1102) was better conveyed by the new DACs.

Despite the tradeoffs, I wouldn't characterize the 1702 DACs as an upgrade. I enjoyed the original Numerik's smoother perspective, even if it meant giving up the 1702's superior bass. Some systems—and listening tastes—will tolerate the increased brightness and less clean treble. I therefore advise caution if you're considering changing your Numerik's PCM63 DACs to the PCM1702s: Listen in your own system first.

The third Numerik on hand for auditioning had the 1702 DACs along with the switching power supply. Astonishingly, much of my criticism of the 1702s was mooted by the vast improvement offered by the switching power supply. The Numerik with the SPS was a completely different animal compared to the 1702 Numerik with the standard linear supply. This wasn't one of those comparisons where you go back and forth, cataloging differences and deciding if the tradeoffs make one more musically satisfying overall than the other. The difference was immediately obvious, and a wholesale improvement in every aspect of the sonic presentation.

The most dramatic change rendered by the SPS was the soundstage—particularly the sense of openness and transparency. The SPS Numerik's crystal-clear, hear-through quality was breathtaking—as though a haze had been washed off the music's picture window. This quality increased the music's vividness without adding an etched or analytical character. I could clearly hear all the way to the back of the soundstage, which had layer upon layer of musical information. This stunning sense of depth was enhanced by the SPS-fitted Numerik's ultrafine resolution of depth gradation. I heard many layers of musical images—all slightly separated by a cushion of air. This spatial resolution was extraordinary by any measure.

The great Zappa record The Yellow Shark (Barking Pumpkin R2 71600) was particularly well-served by this improvement: I could hear more easily what each instrument was doing—a big plus with this complex music. Even though this record was made with less than purist recording techniques, through a good digital decoder it has an amazing sense of layering and depth.

In addition, the SPS Numerik's bass was clearly the best of the three—clean, tight, articulate, and with greater authority. The bass playing on the McLaughlin disc was even more detailed and precise with the SPS, and I felt a greater sense of the interaction between McLaughlin and bassist Dominique Di Piazza.

Footnote 2: The Mark Levinson No.30 Reference Digital Processor uses a switching supply for the digital circuits.—Robert Harley

Footnote 3: This is a perfect example of how implementation affects the sound more than the device itself: the Theta DS Pro Generation III, which uses the PCM63, has stunning bass. Nonetheless, certain DACs can have fundamental limitations, suggested by my auditioning a wide variety of processors using the Crystal CS4328 DAC.—Robert Harley

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