Digital Processor Reviews

When a manufacturer sets out to design and build a product, be it in high-end audio or any other field, the final retail price is usually a prime consideration. Parts and assembly are only part of the equation; there also must be enough buyers to amortize the design and development costs. If the product is to be a flagship model—something a company hopes will give a lift to its entire line—engineers will sometimes throw caution to the winds, designing a product without thought to its ultimate price, which is only set after the design is complete. When Madrigal Audio Laboratories set out to design their No.30 Reference Digital Processor, they appear to have chosen exactly this approach.

By all accounts, the No.30, reviewed by RH in Vol.15 No.1, with "Follow-Ups" by JE and RH in Vol.15 No.7 and Vol.16 No.6, respectively, has been extraordinarily successful. But it is one expensive piece of electronics, filled with every technological wrinkle that Madrigal could conceive of that might possibly improve the sound of digital playback—plus more digital inputs and other goodies than the average audiophile could possibly use. Plus a separately housed power supply larger and heavier than some amplifiers—yet still smaller than the No.30 processor itself.

It comes as no surprise, then, that our subject here, Madrigal's "affordable" answer to the No.30, the new No.35, is smaller, lighter, cheaper, and contained entirely in one chassis. But in terms of affordability, the No.35 is still well beyond the limits of most of our Visa cards. Nevertheless, its designers have managed to bring it in at just over half the price of the No.30—a significant accomplishment.

What have they sacrificed? There are still enough digital inputs on the No.35 to support three high-end systems. The user has a choice of two AES/EBU inputs (a balanced, professional standard which uses XLR connectors), two standard RCA-type coaxial inputs (more properly referred to as S/PDIF, or Sony/Philips Digital InterFace), one ST;r fiberoptic input (also sometimes referred to as an AT&T-type input—AT&T owning the "ST" trademark), and two standard TosLink fiberoptic (EIAJ) inputs. In comparison, the No.30 has eight inputs (five AES/EBU, one ST, two EIAJ, no RCA). The No.35 has one pair each of unbalanced and balanced outputs—two pairs of the latter are furnished on the No.30.

Two digital outputs—AES/EBU and EIAJ—are provided to route the selected digital input to other equipment, if desired. Front-panel selection of a specific input illuminates both input and sampling-frequency LEDs; selection of an AES/EBU input and the activation of de-emphasis circuitry (on those few discs which require it) are also indicated by LEDs. A polarity-reversal switch is also provided (the function of which can be duplicated by the switch on the remote control for the No.31 transport, if the 31 and 35 are joined by their umbilical). The only other control on the front panel selects between full operation and a standby, or warm-up, mode. Changing inputs during operation results in a gradual fade-out of the previously selected input and fade-in of the new input—a slick touch also present on the No.30.

Additional connectors on the rear provide for non-signal, special-function data-links with the Levinson No.31 transport and other current and future 30-series products. They do not provide for clock-slaving between the No.31 transport and the No.35. As with the No.30 D/A processor, Madrigal apparently feels that such linkage would be superfluous given the level of performance they have designed into the 30-series components. They also do not want to discourage use of the No.35 with other, existing components in a user's system or give the user the impression that the performance of the No.35 will be somehow "compromised" if it cannot be clock-synchronized with a transport. The No.30 adds a more elaborate front-panel alphanumeric indicator and a digital record-play loop, but is otherwise very similar in functions to the No.35.

There isn't much wasted space in the No.35's well-organized innards. Careful layout, design, and internal shielding are said to prevent adverse interactions which might otherwise result from such densely packed analog and digital circuitry.

The No.35's Digital Interface Receiver, based on a new monolithic device from Crystal, is less sophisticated than that of the No.30, but is similarly designed for low-jitter performance. (The No.30 uses a proprietary module with separate phase-locked loops for each standard sampling frequency of 32kHz, 44.1kHz, and 48kHz; the No.35 has but one such loop for all frequencies.) The same 8x-oversampling digital filtering is used as in the No.30. As in the No.30, the No.35 uses Levinson's 20-bit DRDAC (Dual-Reference Digital-to-Analog Converter), a proprietary variation on the UltraAnalog chip. The conversion is fully balanced, with separate dual DACs on each channel for the inverted and non-inverted legs.

Separate power supplies are used for analog and digital sections within the No.35. The supplies are necessarily less sophisticated than those in the No.30, but multi-stage electronic regulators isolate the critical circuits. A separate, shielded compartment at the rear of the chassis further limits unwanted power-supply interference.

Last but by no means least, the No.35's audio section, including the analog output stage, is identical to the No.30's, with one exception: the No.30 uses Teflon circuit boards instead of the No.35's less expensive glass-epoxy boards.

Sound
At the risk of giving away the farm before plowing the field, I'll state right up front that the Mark Levinson No.35 is absolutely state-of-the-art. Used with the right transport, it provides digital playback which will likely satisfy all but the most unrepentant digiphobes. It may not stop your yearning for the "good old days" of analog LPs available on every street-corner, but it points the way to a digital future worth looking forward to—a future that is here today in the No.35, though for a price.

The No.35 does not knock the best of last year's digital playback into the weeds—certainly not its big brother, the No.30 (of which I'll have more to say further on). And not even the best of the rest, on which it builds in subtle but important ways. What the No.35 provides is a balance of strengths from the top to the bottom of the audible range. Nothing I have heard can clearly better it overall; nothing I directly compared it with could unequivocally better it in any respect. There will certainly be room for argument in both of these conclusions, and new processors are entering the market every day to challenge for King of the Hill. But the pace of digital development, in terms of sheer sound, is slowing somewhat from the furious pace of the late '80s. The challenge now is to provide more for less. Expensive as it is, the No.35 is substantially lower in cost than the No.30.