Perhaps I shouldn't have been surprised when I first spied the prototypes for Sonic Frontiers' luscious new digital combo, the Transport 3 CD transport and Processor 3 D/A processor, at HI-FI'97 in San Francisco. After all, this is the company whose meteoric rise from an electronic parts-supply outfit run out of president Chris Johnson's basement to a large factory pumping out an impressive array of entry-level to creme de la creme tube electronic components has elevated Sonic Frontiers to front-line status among high-end manufacturers.

In many ways, the Sonic Frontiers (SF) story defines the high-end entrepreneurial spirit. (See the SF interview with Robert Deutsch in Stereophile, Vol.19 No.6.) Remember, too, that the company's first foray into digital - the original SFD-2 processor some five years ago - was met with near-universal acclaim and a Class A rating in Stereophile's "Recommended Components." SF maintained that Class A status with the SFD-2 Mk.II and the SFT-1 transport.

In spite of Sonic Frontiers' admirable track record, I was surprised at the ambitious scale of their new designs, most visible in the radical look of the Transport 3 and its iris-ported disc-loading mechanism, but even more impressively apparent under the skin of the Processor 3.

However, after a careful examination of the Processor 3 prototype in SF's St. Francis Hotel suite at HI-FI'97, where it was on silent display, it was obvious that this was no mere souped-up SFD-2 Mk.II, but an all-new animal with several substantial engineering advances. Features that first caught my eye were its outboard power supply, discrete I/V conversion, and I²S-Enhanced interface designed by UltraAnalog, who had a major hand in the overall design of the Transport 3 (T-3) and Processor 3 (P-3). (I2S stands for Inter-IC-Sound.)

Could the Sonic Frontiers/UltraAnalog team have outdone themselves again, and not with just another Class A processor, but one that could redefine the Class A category? And what about the slick new T-3? Could its performance match its way-cool looks? More important, could a CD-only transport sporting a price tag a buck shy of $7000 find a place in the uncertain, rapidly changing world of digital audio? These and other questions placed both products at the top of my HI-FIÔ97 wish list. But before we get to my answers, let's take a closer look at the make-up of both units.

Transport 3: An EYEris for the refined
I've seen transports that are more flashy or ornate than Sonic Frontiers' new show-stopper, but the Transport 3 is wonderfully slick, clean, and elegant - to my eye, one of the most attractive disc-spinners yet. The transport is quite large; viewed from the front, the width of the chassis -dominated by 5/8"-thick machined aluminum exterior plates sporting a shot-blasted, clear-anodized finish - is offset by its low-profile height of only 3 1/4". Add the special 1"-high Sorbothane isolation feet supplied by E.A.R., and the total unit height reaches just over 4".

The aluminum faceplate establishes the transports clean look and is maintained throughout the design, with the exception of SF's trademark black front bezel, within which is centered an easy-to-read green LED display and a small power button. All other chassis-mounted controls are arrayed in a graceful arc on top of the device along the front night side of the disc-loading mechanism.

It's the disc-loader that gets the most oohs and aahs. Centered on the top plate of the transport is an aluminum ring 12" in diameter and 5/8" thick, with a hole slightly more than 6" in diameter cut in the center. When open, this hole exposes the transport's laser pickup, tracking sled, and disc spindle. Position a CD on the extended portion of the spindle, place the small magnetic cap on top of it to secure the disc while it rotates (this disc clamp meets the Philip's standard for total mass to prevent excess motor stress), and press Close: Five vanes, each shaped much like the dorsal fin of a great white shark, rotate inward from their concealed positions beneath the outer ring to seal the opening tightly, with an action similar to that of the iris shutter on an SLR camera. This proprietary mechanism is driven by a precision Swiss motor and is definitely cool to watch as it makes a distinct whirring sound not unlike the meat slicer at a local deli (though considerably quieter). With a CD spinning underneath, opening and closing the iris hatch really does look like an eye from an M.C. Escher painting winking at you - or, depending on your frame of mind, an exit door on one of the motherships in Mars Attacks!

The rear panel offers a full set of digital outputs, including an AES/EBU, S/PDIFs of both the RCA and BNC varieties, ST-Type glass optical, the all-important I²S-Enhanced 13W3 output connector, and an infrared port for linking the transport to an outboard IR repeater. Of course, there's a standard IEC power inlet as well.

Though only three flex-head screws connect the aluminum side plates to the thick top lid, if you feel the need to gaze at the T-3's innards, be careful. Lift the lid slowly and only slightly-the transport mechanism itself is mounted to the bottom center of the heavy lid, with control, signal, and power wiring connecting it to the main board and power supply.

What you'll see will be three circuit boards and the various connectors mounted inside a 14-gauge black-plated sheet-metal subchassis, to which the side and front machined aluminum outer plates are attached. The largest board is a long L-shaped, dual-sided, solder-masked pcb that runs along the left side and rear section of the lower sub-chassis. This board contains the circuitry for all the output options. The 12 regulated low-impedance, ultra-low-noise power supplies spread across this board are fed by a large custom-built toroidal transformer in the upper right corner of the subchassis. The total capacitance of these supplies is around 25,000µF, close to that of some small amplifiers!

Also on the T-3's main board is a "proprietary" AT cut-crystal master oscillator to provide precise timing for transport functions, as well as for the word clock feeding the outboard digital processor According to Chris Johnson, great care was applied in the execution and layout of these dual-cascaded, RC-filtered voltage regulators to provide DC power with the lowest noise possible for critical clocking functions, and to ensure the greatest immunity from phase-noise contamination of the jitter spectrum. I suspect that this feature and the I²S-E interface are two of the biggest contributors to the unit's rock-solid performance. The transport mechanism is a relatively new version of Philips' Professional CDM-12, and was specifically designed for top-loading players. It incorporates a rigid die-cast construction, a three-beam optical system, and a unique servo processor claimed to enhance the T-3's disc-tracking ability.

Wrapping up the transport package is a 13W3-I2S cable and a very suave little round, flying-saucer-like remote control. This remote is a real gem; it rides nicely between one's thumb and middle finger, leaving the index finger free to operate the buttons. As a reviewer, my only complaint is the inability to select specific track numbers when jumping around a disc containing many tracks, something I do often when making A/B comparisons of different components. However, I doubt this will much inconvenience the average user. A generic plastic remote is also available if keypad functions are desired.

Processor 3: Stretching the limit The Sonic Frontiers Processor 3 is a two-box affair featuring a fully differential, balanced topology in both the analog and digital domains. The large main chassis is attached to the smaller (though still hefty) outboard power supply via a 61/2" detachable cable. Like the T-3's, the P-3's front panel is easy to read from a distance, displaying locked sample frequency and selected digital inputs.

The power supply is a beefy, straight-forward design with a large potted transformer feeding six stages of regulation within the power-supply chassis. Several of these primary regulators are, in turn, cascaded to other stages within the main unit for a total of 14 regulators serving the processor. All but two on the analog output board use Linear Technologies low-noise version of the popular 317/337 three-pin devices.

The main chassis contains three large circuit boards partially overlapping one another above the floor of the unit, as well as a fourth, vertical board assigned to front-panel duties. Of prime importance for the prospective buyer is the manner in which these boards are laid out. With the emergence of higher-resolution digital formats, I feel it would be folly to plop down a large sum for a processor that wasn't easily updateable, regardless of how good it makes CDs sound. SF obviously had this in mind when designing the P-3, and has carefully configured the principal boards to anticipate new developments. For example, the front-panel board already supports display of 88.2kHz and 96kHz sample rates.

The digital input board contains six interface options, selectable via front-panel buttons, including counterparts to all of those found on the T-3, plus TosLink. All input signals, other than that from the I2S-E interface, are routed through an AES21-C002 encapsulated input receiver for recovery of the clock and data. Also on this board is the now-ubiquitous PMD-100 HDCD digital filter, but with a wrinkle. Much has been made of the 6dB of attenuation required by Pacific Microsonics to be applied to all non-HDCD discs for level matching with HDCD-encoded software. A DAC designer can choose to implement this signal reduction in either the analog or digital domains, though each technique has potential compromises. The P-3 I reviewed bypassed this attenuation altogether, and did so while eliminating any extra resistors or relays in the signal path. A simple jumper is located just before the PMD-100 chip. Therefore, if you find it annoying to have to adjust the volume on your pre-amp when switching between HDCD and non-HDCD discs, you can easily engage the specified gain-scaling for regular CDs, in this case applied in the digital domain with a resultant 1-bit loss of resolution.

The second and largest circuit board runs across the entire front of the processor and is made of Arlon, an expensive Teflon/Fiberglass hybrid said to be ideal for delicate high-speed signal-processing applications. Chris Johnson says that it is one of the largest Arlon boards ever made. The other two dual-sided boards are of FR-4 glass epoxy.

Four separate stages of regulation are found just prior to the two dual 20-bit UltraAnalog D20400-A DAC modules, providing a discrete stage of isolation and 5V power-supply conversion for each internal DAC, each of which, in turn, serves a separate channel phase. These DAC modules are UltraAnalog's best, but with a major enhancement applied within the P-3. Most other versions of the D20400-A DAC incorporate the critical current-to-voltage (I/V) conversion circuitry within the DAC module, usually a high-speed op-amp from companies such as Analog Devices or Burr-Brown. In this instance, UA designed an outboard I/V conversion module made up of some 75 discrete surface-mount components per channel. According to Chris Johnson, "this novel circuit has significantly better low-level IM-distortion artifacts than their previous integrated I/V stages." Johnson also credited much of the P-3's reported ultra-low noise floor to the new I/V design.

After voltage conversion, the signal goes through analog reconstruction via a discrete, third-order, passive LCR filter for each channel phase. It's a point of pride for Johnson that SF was able to implement this new reconstruction filter with minimal high-frequency attenuation at 20kHz by using a variation of a Chebyshev design.

The final board of interest is chock full of discrete circuitry supporting the four 6922 dual-triode tubes - double the tube count of the SFD-2 Mk.II - that form the heart of the processor's analog output stage. Each channel phase has one dual triode with its internal sections connected in parallel, effectively resulting in eight tubes within four bottles for a 3dB reduction in noise and a halving of the output impedance. Furthermore, the output stage, a cathode follower with solid-state current sources, eschews the coupling caps of SF's previous processors. Instead, it employs a direct-coupled design via surface-mounted servos on the bottom of the board, resulting in a largely frequency-independent output impedance, as first seen in SF's highly touted SFCD-1 CD player. These servos are accompanied by a "failsafe" circuit that ensures that no DC can pass to the outputs in the event of servo failure. UltraAnalog's Richard Powers said that "you can even yank a tube while the unit's on without any DC surprises." Rather than test this claim, I took his word it, and suggest you do as well!

The P-3 also has a shunted mute relay that remains out of the signal path, and a second-order output low-pass filter to attenuate RFI from riding down the interconnects. (By the way, if your preamp lacks the ability to set different gain levels for various sources, be very careful when switching to the P-3 from any other input. The unit outputs a healthy 3V from its unbalanced RCA jacks, and a whopping 6V from its pair of balanced XLR connectors!) All in all, a very impressive piece of engineering, and ample proof that the SF/UA team pulled out all the stops to build the quietest and best-sounding digital processor they could, regardless of price.

Means and methods
My experiences with the Processor 3, followed much later by the Transport 3, took place in two distinct phases. The initial stage began in the fall of 1997, after an early production P-3 arrived at my Honolulu apartment. At the time I was in the midst of an extended sabbatical from these pages as I oversaw the design and construction of my new home, into which I finally moved this past May. (My empathy is extended to all who've been through that mind-numbing experience.) Eager as I was to experience the P-3 in its best light, I immediately connected its 13W3-I²S-E connector to a Muse Model 5 transport. Unfortunately, I could get no signal lock, even though the Muse unit was equipped with a fully functional 13W3-I²S output. (SF itself had not yet released a transport with an I²S-E option.) My dismay increased after I discovered, through phone calls and e-mail to both companies, that each was using a different and incompatible version of the I²S transmission interface! (See sidebar, "I2S: Two Don't Always Tango.")

Despite this early setback, I had no problem at all adjusting to the P-3's extreme clarity, dynamic dexterity, and wide-band performance when using the AES/EBU and S/PDIF interfaces from either the Muse Model 5 transport or a modified Theta Data II. In any event, while I was steeped in house-building, most of my time with the P-3 was spent enjoying a vast array of music rather than doing in-depth analytical listening.

Phase Two began after I'd installed the astounding new quad-amplified Audio Artistry Beethoven Grand speaker system, with its all-active crossover, in the substantially larger listening room of my new home. This house has background noise somewhere on the order of Grant's Tomb, and, combined with the remarkable resolution and openness of these speakers, revealed subtle sonic variations between components that were simply burned at my previous digs. Accordingly, my discussion of performance issues will be restricted to my most recent experiences of the products in my new home. The picture was completed a few days after HI-FI '98, when the Transport 3 arrived and I could get down to business.

Despite the overall convergence of absolute sound quality between most competently designed transports and processors, sonic differences do exist between otherwise well-made top-tier gear. However, these differences tend to be very small. With this understanding, you can interpret my often liberal use of analogy in the proper context as I attempt to convey those portions of my experience that will most likely be translatable to your own. Therefore, while the following characteristics are shared to one degree or another by a number of other front-end digital components I've heard, Sonic Frontiers' Transport 3 and Processor 3 stood out from this select crowd in the areas of performance outlined below.

Sonic Delight: The Processor 3
The overall sound of Sonic Frontiers' Processor 3, using one of its standard non-I2S interfaces, was actually closer to that of SF's SFCD-1 (Stereophile, Vol.19 No.6) than to the SFD-2 Mk.II. The latter model had two principal short-comings in its otherwise excellent performance: I often found its bass rendition a bit too bloomy and diffused, and its perspective was a little forward for my taste - even though that forwardness often made for some spectacular dynamics and rhythmic drive.

In contrast, the P-3 not only exceeded the large-scale dynamic articulation of the SFD-2 Mk.II, but did so with notable refinements in low-level dynamic resolution, and with a more relaxed, though not too distant, spatial perspective closer to that of the SFCD-1. I suspect that this fundamental improvement owes much to the P-3's ultra-low noise floor. This ability to so effortlessly paint each instrument with just the right amount of dynamic shading within the larger context of the tempo's ebb and flow was a hallmark of the P-3, and often made listening to even mundane CDs an involving experience.

That the P-3 conveyed awesome transient delineation shouldn't be surprising in light of its world-class resolution of subtle contrast. Its stellar transient clarity and ultra-quiet background imbued music of all stripes with alluring tangibility and purity. This quality was revealed by the ease with which I could hear the full expression of both complex transients and the most delicate harmonic decays even in the very midst of a powerful crescendo, and without the slightest smearing or congestion between of the two. Time and again, percussive and stringed instruments struck a perfect balance of stunning articulation and graceful rhythmic poise without ever seeming overbearing. Indeed, this was the best transient performance and dynamic contrast I've yet heard from CD.

The P-3's tonal balance was also very neutral to my ears, certainly more so than that produced by previous SF digital products. This unit was a thin sliver on the light side of neutral, but not even close to being bright or harsh when playing natural, well-made recordings. The P-3's bass performance was a big leap forward from that of the SFD-2 Mk.II. There was nary a hint of the P-3's tube pedigree apparent in the bottom end. The low to midbass was delicately textured and tuneful, yet capable of substantial impact and authority. I've heard one or two units whose overall low-frequency timbre is a shade richer than the P-3's, though I'd be hard-pressed to call it more accurate. The midrange was hard to fault by any standard, while the treble sounded more extended and open than any unit I've had in my system. Perhaps the combination of the processor's flat yet delicately balanced upper treble, with its superb transient focus, contributed to the slightly light tilt of its overall tonal character.

Of course, most of these sonic traits are interrelated; in the P-3 they jelled to wide present a wide-open, continuous sound-field in the front half of my listening room that seemed uniformly alive, with a luminescent quality within which the correct physical proportions of instruments and vocalists were perceived. This was in contrast to the tendency to spotlight individual sonic images within their own immediate acoustic envelopes that can be heard from otherwise decent components that lack the last measure of ambience resolution I heard from the P-3. These soundstaging attributes were particularly apparent on supremely natural-sounding discs such as Stereophile's new Duet (STPH012-2). The opening track of Erwin Schulhoff's Sonata for Solo Violin teleports me every time to the Santa Fe chapel where this piece was recorded. Through the P-3, that feeling of genuine presence takes on an extra measure of realism.

Another example of the P-3's resolution prowess was in the alternating, marchlike build up and release of musical tension throughout the opening title track of Mephisto & Co., Reference Recordings' recent and Witches Brew-like HDCD-encoded compilation (RR-82CD). I never heard the P-3 congeal or compress an orchestral climax. This is lesser designs, and of earlier digital in general: when the going gets tough, the soundstage tends to smear and flatten, often becoming aggressive and shrill. Other HDCD recordings also sounded their best yet through the P-3. However, many of my favorite discs lack such encoding; using HDCD-encoded software when comparing this processor to models employing other digital filter techniques tends to stack the deck. Therefore, most of my direct comparisons with other components were done with non-HDCD recordings.

With the Transport 3
So far, all of my comments regarding the P-3 were gleaned from using one of two Muse transports (the Model 5 CD-only, and the new Model 8 DVD/CD spinner), my souped-up Theta Data II, or the PCM output on a Pioneer DV-500 DVD/CD player. Digital links were many, but I primarily used the Kimber/ Illuminati Orchid and Cardas AES/EBU, as well as S/PDIF cables from Illuminati, MIT, Cardas, and Mango.

Hooking up the Transport 3 to the Processor 3 showed the synergistic match between the two Sonic Frontiers components, even without the I²S-E connection. The T-3 driving other processors was truly formidable as well. Using standard interface options, consistently experienced a degree of enhanced focus and a bit more solidity to some images and their acoustic environments compared to that from the other transports tested, regardless of the processor used.

However, the real news with the T-3 was the impact of connecting its I²S-E output to the P-3. I felt as if I'd just put on a new pair of glasses! Every virtue of a good I²S connection described in the accompanying sidebar was added to the P-3's inherent attributes outlined above! Dynamic contrast and low-level harmonic details became even more focused, while the whole presentation took on a notably greater degree of ease and presence. Sibilants also sounded more natural. Without I²S-E, the T-3/P-3 combination is a definite contender for the brass ring among current Class A digital rigs. With I²S-E, the pair stand at the pinnacle of the CD hill, in my experience.

The Digital Conundrum
The compact disc no doubt has many good years of viability ahead of it, and I can't think of a better way of getting the most out of that format than by using both of Sonic Frontiers' new CD source components. Had their I²S-Enhanced-equipped Transport 3 and Processor 3 been available over a year ago, I could have easily recommended them without qualification to those searching for cutting-edge CD play-back. It's obvious that I was smitten by their standard-setting performance, excellent ergonomics, and great looks. As it is, though, the watershed format changes now upon us add the following caveats to my recommendations.

Obviously, only well-heeled audiophiles, or those who simply must have the best and are willing to go deep into hock, will be in the market for a $14,000 digital front-end. Evidence indicates that there are a fair number of music lovers in each category. For these groups, I readily endorse SF's T-3/P-3 combo as the highest example of the CD art I've heard so far. Indeed, if this fits your description, you should consider both products as a single-purchase, two-box CD layer rather than as separates - that is, as long as you can envision owning a separate transport for CDs and another for DVD A/V discs, both of which could be connected to an upgraded Processor 3 when the proposed standards are finally sorted out and more hi-rez 96kHz software becomes available. There's also a far smaller category of very wealthy individuals who buy and sell top-tier components regularly for the sport of "having owned the best," and who will certainly want to add this combo to their quivers.

However, even though the Transport 3 is the best-sounding CD transport I've had in my system, and a true joy to operate, I can't endorse a $6999 disc spinner as a stand-alone unit for most audiophiles - particularly if they expect the transport to be upgradeable to DVD status. Such a mod would likely be very expensive and complicated, if not impossible. Instead, I suspect that SF will incorporate many of the advances seen in the T-3 into an entirely new DVD-based model in the near future.

The Processor 3, on the other hand, has such well thought-out modularity, such low inherent jitter, such a quiet noise floor, and such world-class sonics that it easily earned five stars with a bullet as a stand-alone unit for playing CDs. I'm also confident that it will provide a solid platform for DVD-based audio processing when SF and you are ready to make that jump. In addition, though Sonic Frontiers' I²S-Enhanced interface will likely require some modifications to comply with the demands of the new format, it's perfectly fine for the CD medium.

A final category of audiophile for whom the P-3 is particularly stilted are those who either own or can buy a used SFT-1 transport or SFCD-1 player, both of which SF will upgrade to I²S-Enhanced status for $700, including cable, daughterboard, and sheet-metal modifications. (It's well worth it.) While that won't match the ultimate performance of the T-3/P-3 combo it'll get you very close indeed.

Has Sonic Frontiers really outdone themselves again? Yes, indeed!

Analog source: Immedia RPM-2 turntable and Unipivot arm, Sounds of Silence Crown Jewel cartridge. Digital sources: CD transports: Sonic Frontiers SFT-1 with I2S-E, Muse Model 5 with 13W3-I2S, modified Theta Data II; Muse Model 8 DVD/CD transport with 13W3-I2 S, Pioneer DV-500 DVD/CD player. Digital processors: Muse Model Two-Plus, CD only, with 13W3-I2S; Muse Model 296, 96kHz, with 13W3-I2S; Theta Gen.V-A. Preamplification: Z-Systems rdp-1, BAT VK-3i, Muse Model 3 preamplifiers; Jeff Rowland Design Group Coherence II preamplifier, Cadence phono stage. Power amplifiers: Jeff Rowland Design Group MC-6 six-channel amplifier for tri-amping main speaker panels, two Model 6 monoblocks for driving a pair of subwoofers. Loudspeakers: Audio Artistry Beethoven Grand. Cables: Interconnects: Cardas Neutral Reference, BEL The Wire, Discovery Signature, Immedia phono. Digital Interconnects: Cardas AES/EBU, Kimber Illuminati Orchid, Marigo Reference, Discovery, MIT, AudioQuest for both AES/ EBU and ST-Optical, Aural Symphonics AES/EBU, BNC, and ST-Optical. Speaker cables: Cardas Golden Cross, TARA Labs Decade, Discovery, Nordost Red Dawn, Goertz. Power cords: Cardas, Audio Power, Marigo Reference. Accessories: Arcici Suspense isolation stand, Mike Fredericksen stands, Townshend Seismic Sinks, Signal Guard platform, D'Feet isolation pucks, ASC Tube Traps, Vibraplane pneumatic isolation platform (turntable), Newport Bench- top pneumatic isolation platform with Jun-Air compressor (transports), Audio Power Ultra Wedges 112,115,116, PE-II. Ñ Shannon Dickson