Mark Levinson No.30 Reference Digital Processor Page 3

Perhaps the most unusual aspect of the No.30's design is the two towers that contain the D/A converters and analog output circuitry. Besides giving the No.30 its distinctive look, there were some important engineering reasons for isolating the analog circuitry from digital signal processing and control signals. The towers are virtually immune to radiated noise, both by their shielding and by their distance from the digital electronics. More important, however, are the thermal conditions under which the critical conversion to analog takes place. The towers were very carefully designed to maintain a constant high temperature, unaffected by the outside temperature. Further, no temperature variations exist within the towers that could affect D/A conversion. The enclosed modules maintain a carefully chosen thermal balance between the module's large heatsink and its internal heat-generating components. Because the modules are too hot to touch, they are surrounded by the black outer chassis.

Madrigal strongly believes that thermal gradients around the DAC severely degrade conversion accuracy. When considering that the Least Significant Bit (LSB) in a 20-bit system produces an output voltage on the order of a few µV, it's plausible that temperature stability plays a large role in accurate D/A conversion.

Each tower contains analog supply-regulation stages, a dual DAC, and an output buffer. The ±15V regulator is a discrete hybrid stage identical to that found in the PLS-330. D/A conversion is performed by two UltraAnalog C009 dual 20-bit DACs custom-made for Madrigal. One dual DAC per channel is used for true differential operation. The double-differential signal from the DSP board is converted to a single-differential signal on a small sub-board within the tower.

The analog output stage, mounted on a Teflon pcb along with the DACs, is an all-new discrete circuit that, according to Madrigal, achieves "sonic neutrality superior to that of any previous Mark Levinson product." This unity-gain buffer features no AC feedback in the audio range, a DC servo circuit to eliminate coupling caps in the signal path, and an output stage cascoded with a current amplifier to preserve class-A operation while minimizing voltage changes across the output. Muting relays in the output stage prevent noise or pops from reaching the output during power-up or power-down.

Like Madrigal's other digital products (the Proceed line), the No.30 has a very low output impedance (specified at <6 ohms). Output low-pass filtering is an active Bessel-aligned type with constant group delay to 40kHz. This filter's design was reportedly critical in maintaining the processor's sense of dynamics.

Despite the length of this technical description, the No.30 includes many elaborate techniques I haven't mentioned; it's just chock-full of innovative design and uncompromised execution, the latter clearly dictated by sound quality, not efforts to meet a "price point." However, Madrigal claims that every technique and circuit refinement in the power supply and No.30 had an audible effect. If their ears heard an improvement, the technique was incorporated. If they didn't, it wasn't. The No.30 is thus the defining physical embodiment of Madrigal's D/A converter philosophy.

It probably goes without saying, but the build integrity, parts quality, and fit'n'finish are extraordinary. In fact, the No.30 is the most beautifully built and elaborately designed audio product I've ever seen.

To say I was eager to hear what this technological marvel sounded like is an understatement.

From the very first moment of listening, it was obvious that the No.30 was something special. This was clearly digital playback many levels above what had been previously considered the state of the art.

As I sat in my listening chair through the first piece of music, I was overwhelmed by the sheer amount of musical information revealed by the No.30. It was as though a translucent window had been removed from between me and the music, allowing previously obscured detail to become vibrant and lifelike. Suddenly, I realized the implications of what I was hearing: if music I knew so intimately had this many more levels of detail and nuance, perhaps all digital media had a hidden musicality waiting to be revealed. It was an exciting prospect.

The next few hours were revelatory. With disc after disc, the reaction was the same: music known intimately was presented in a way that made me feel as though I were hearing it for the first time (footnote 3). In addition, I felt that I was hearing just the music, not a digital processor's interpretation of it.

Specifically, the No.30 exceeds the performance of every other converter in every criterion I use to assess digital processor quality. From detail resolution to soundstaging to dynamics to tonal neutrality, the No.30 was in a different league.

Starting with the bass, the No.30 had a combination of tautness and dynamic impact that was stunning. The entire bottom end was tight as a trampoline, punchy, and with superb pitch resolution. In jazz with acoustic bass, the instrument took on an entirely new character: round, liquid, controlled, and very dynamic. These qualities added greatly to the music's rhythm and drive. In addition, the bass seemed to stand out, existing independently of the rest of the presentation. The impression of a bass player standing there playing was palpable. Further adding to the sense of presence, the low frequencies had a liquidity and wealth of inner detail that made instruments sound just plain real. The stultified, wooden, featureless bass presented by some digital processors was thrown into sharp relief by the No.30's liquid, finely woven rendering.

The bass also had a remarkable clarity and solidity. On the Dorian recording of Jean Guillou's organ transcription of Mussorgsky's Pictures at an Exhibition (DOR-90117), the very low pedal tones were each clearly articulated and differentiated. By contrast, other converters' low ends could sound like a roar, degenerating into a jumble of indistinct tones. This was especially true at high levels and during complex passages. This recording highlighted the No.30's ability to maintain pitch definition and clarity, no matter the demands placed on it.

The No.30 presented a very "fast" low end. Bass drum had a suddenness and steep attack not previously heard from digital. There was a sense of dynamic effortlessness that was startling. The combination of remarkable pitch precision with unhindered dynamics produced greater impact and power. The musical effect of the No.30's superb bass reproduction was a heightened sense of rhythm, pace, and drive. There was a bounce and energy to the music that provided a greater impression of musicians playing and interacting with each other. The rhythm section really locked in and cooked through the No.30, bringing a newfound sense of energy. Every kind of music benefited from this sense of pace. From the rhythmic intensity of The Rite of Spring (Chesky CD42) to be-bop (my own recording) to electric blues (Luke and the Locomotives, AudioQuest AQ CD1004), the No.30's drive was exhilarating.

Moving to the midrange, the No.30 had an unparalleled presentation of natural timbres—no glare, hardness, or synthetic artificiality. Instrumental timbres were lifelike and palpable, richly infused with fine detail. The acoustic guitar and fretless acoustic bass on Three-Way Mirror (Reference Recordings RR-24CD) sounded much more real when fleshed out with such textural purity and delicate nuance. This is an area where the No.30 has no peer: the ability to resolve the subtleties that make a reproduced instrument sound more like "live." There was a harmonic rightness to textures that made the No.30 sound distinctly "undigital." The hardness and slightly metallic edge of most converters was replaced by a warm smoothness that allowed high playback levels without cringing. In fact, I was constantly tempted to turn the music up rather than down—rare indeed for digital.

The No.30 has perhaps the most "right" and unfatiguing treble presentation of any digital processor I've auditioned. Many converters attempt to gloss over digital's treble hash by making the top octaves overly soft and syrupy. This gets rid of the whitish grain overlaying the music, but also robs it of detail and richness. The No.30 paradoxically provided a silky-smooth treble and lots of detail. The only other digital source with this smooth a treble balance that doesn't overly romanticize the presentation was the Linn Karik CD player reviewed last month.

Instruments rich in high frequencies were beautifully portrayed by the No.30, completely lacking that fatiguing brittleness so often heard from digital. On the excellent Harmonia Mundi recording of Nicholas McGegan conducting Handel's Water Music (HMU-907010), there was a warmth and smoothness to the strings that was a revelation. I didn't have to listen past a steely metallic quality to enjoy the music.

In addition, cymbals had a burnished, round quality rather than being overlaid with grain. Even compared to some smooth-sounding processors—the Wadia 2000 and ARC DAC1-20—the No.30 achieved another level of treble purity and sense of ease. Music was relaxing, not edgy. Long listening sessions were free from fatigue, without the common sense of relief when the volume was turned down. I found myself listening at higher playback levels than normal because of the No.30's treble smoothness. Overall, the No.30's tonal balance was just right—tight and full bass, silky treble, and no midrange forwardness.

Footnote 3: My reaction to the No.30 in a very different system—Wadia transport, glass-fiber datalink, Mod Squad Line Drive Deluxe, Audio Research Classic 120 monoblocks, Spendor S100 loudspeakers—was identical. One CD led to another to another to another; a common experience with LP, but a first time for me in nine years of CD playback.—John Atkinson
Harman High Performance Audio/Video Group
1718 West Mishawaka Road
Elkhart, IN 46517
(516) 594-0300