Sonic Frontiers Phono 1 Phono Stage
Part II: Bridging the Gap between Tube and Transistor Sound
by Myles B. Astor

December 1998 Volume 1 No.5

Dynamics or low-level resolution? Purity of tone or noise levels? Until recently, these were the choices audiophiles using extremely low-output moving coils (less than O.5 mV) faced when deciding between solid-state or tube preamplifiers. Those opting for the latter option lived with the high noise levels and "tube rush" that intruded upon the music during the quieter passages. And that level of quietness only lasted as long as the tubes remained quiet! Luckily there are new phono sections, such as the Sonic Frontiers Phono 1 Phono Stage, that make those tradeoffs bad memories.

A QUICK RECAP!
I was in the processs of wrapping up the Line 3 review when Chris Johnson, President of Sonic Frontiers, informed me that the Phono 1, the companion phono section for the Line 3, had just become available. Given the Line 3's relatively low gain (12 db), it only made sense to see how Sonic Frontiers new phono section, in contrast to the cj Premier 15, worked with their own line stage. As it turns out, both the Line 3 and Phono 1 share the same strengths: transparency, detail and quietness.

But before getting to Sonic Frontiers Phono 1, I'd like to spend a moment discussing the Line 3's headphone amplifier. As Dayna b. points out in her Holmes-Powell review, most audiophiles eschew headphones (and Im not completely innocent). Headphones give a very different listening experience; there's not the imaging you hear with speakers but there is far more detail. So after wrapping up the Line 3 review, I procured some Grado Reference RS1 headphones and gave the headphone section a once-over. I wasnt disappointed.

The sound was rich and warm in the midrange; little details abounded; the music exuded life. The main complaint, a loss of definition and hump in the bass region, is as attributable to the headphones as it is to the Phono 1. Then there's the ability to correct for out-of-absolute-phase recordings with the remote control. Many of my favorite recordings, such Jacques Bittners Pieces de Luth-1682 (Accent 8227), were often just a little fuzzy and unfocused. Now, a push of the button and, presto, the lute snaps into focus.

NEUTRALITY AND NOISE FLOOR
Bittners Pieces de Luth-1682 is a perfect segue into the Phono l's strength, its low noise floor. The engineer close-miked the lute and, as a consequence, the instrument is somewhat larger than life. Every breath Konrad Junghnel takes is recorded for posterity, as is his wonderful playing. The engineers miking captures the delightful reverberation of the lute, its light, airy quality and cavity resonance, the delineation of each attack and decay. No noise intrudes upon the music, even during the softest passages. In fact, the only noise is the hiss of the analog tape. Nor does the sound emanating from the body of the lute obscure his playing of the instrument, as some other phono sections are prone to do.

There's the inherent noise in the electronics and then there's how the equipment deals with record surface noise. In general, LPs sound noisier when played back using solid-state gear (or accurately recreated, depending on your point of view). By contrast, the same record surface noise is barely, if at all, audible through tube preamplifiers (analogous also to the difference between linear tracking, air bearing and pivoted arms). The Phono 1 falls into the former rather than latter camp. In fact, the noise floor of the unit is so low that we hear more of the defects in the vinyl formulation.

Then theres the Phono 1's ability to recreate the sound of the original recording venue in this case, a chapel or church. It produces the sense of a large, ambient space and the feeling of Junghnel sitting in middle of the room.
The number of birds chirping outside (really!) is a reminder that the album was recorded in late spring or early summer (it was actually July). The neutrality and speed of the Phono 1 really comes across on Autumn Leaves from Portraits in Jazz: Bill Evans Trio (Riverside OJC 088). There is no trace of any euphonic character on this studio recording. You can hear the recording problems such as the electronic noise endemic to the album. There is speed and flow to the music from Scott LaFaros bass to Paul Motians cymbal work which goes a long way to appreciating the tightness of the trios playing. Portraits in Jazz captures Evans' piano far better than any of his other albums, live recordings included. On Portraits in Jazz, the size of Evans' piano is much closer to reality than his other works. You can tell that the piano lid is open, and the sound of the piano reverberates and projects out toward the listener. At the same time, you have the ability to peer inside Evans' piano. The upper keys of the piano are not hooded or muted. The unit captures the essence of the bass, especially its vibrations and resonance. Motians cymbal work is delicate. The bass is rolled off and you can clearly hear that with the Phono 1. One had better recheck the VTA if the bass sounds slow or less than well articulated.

In fact, I toyed with the setup of the VPI JMW-12 Memorial arm when putting the phono section through its paces. Lowering the damping fluid enhanced the articulation and palpability of the piano. A touch of smearing vanished. When all was said and done, the delineation of the outline of the instrument and its feeling of a three-dimensional radiating surface could be a hair better. The lack of tube rush, or dynamic constriction, really made listening to the music fun. There's none of that turning up the volume and the music gets louder but the dynamics remain the same. This quietness affects the music in subtler ways. On Cowells Pulse from Music for Percussion and Strings (New World 319), individual instruments were more resonant. Wood blocks have a characteristic knock when they are struck. There is a an opening up of dynamics in the p to ff region. On this marvelous recording of modern compositions, there is a dynamic and sonic contrast between the Korean Dragon Mantles (which sound like the performer stepped back from the mike literally, not actually) and the wood block. And you can hear, based upon the sound of the wood blocks, how the Phono 1 opens up the back outside edges of the soundstage. Rice bowls at the beginning of the second movement are metallic, yet slightly deadened. Cymbals have an extraordinary delicacy as the percussionist keeps the instrument ringing with subtle playing. The top end is incredibly open, detailed and extended the opposite of the CD reissue.

A MUSICAL KALEIDOSCOPE
Or try something like the soundtrack to the movie Emerald Forest (Varese Sarabande STV 81244). Here, no matter what the cut, theres a kaleidoscope of sounds and instruments. Every 10 seconds or so, you must turn your head to hear another instrument. Its difficult to sit and review the Phono 1 when you dont want to miss a single magical moment of whats happening on the recording.

What is noteworthy is the Phono 1s ability to remain uncongested, no matter the complexity of the music. Then listen to the African drums which, if you have a system capable of resolving the lowest frequencies, will make your pants flap in the breeze. With the Phono 1, the drums have a tightness that eludes many other phono sections. There is an absence of tubbiness or flabbiness, giving a new solidity to the drums. You can almost count the vibrations of the drum head.

CHOICE OF PERSPECTIVE
The Phono I does a marvelous job of capturing the spaciousness of a hall, which should please analog lovers. Overall, the Phono 1 is a bit stronger at recovering the envelope of sound around an instrument than the overall hall ambience. As a result, on, say, the second movement of Rachmaninoffs Symphonic Dances (EMI AS 3259), there is more of a feeling of direct rather than reflected sound. Flutes and woodwinds have a realistic tone and sense of air. The feeling of ambience of the hall is ever so slightly decreased, giving the impression of sitting more onstage with the musicians.

What really struck me on this recording was the Phono 1's abilty to reproduce and control massed strings. Other phono sections have a tendency to become bright and a little distorted when massed strings reach a crescendo. The Phono 1 gives you the power of the massed strings but stops right before becoming foward.

The amount of air enveloping the massed strings is much like you'd hear live in the best of halls. And pizzicatos have a real beat to them, not a senseless plucking of strings. I wish strings were a touch richer and fuller, but theyre far from wiry or hard sounding.
Rachmaninoff lovers should check out the Previn recording. The interpretation and sound is far superior to David Johanos conducting the Dallas Symphony Orchestras release on Vox Turnabout (and reissued on the Athena Records label).

A MAGICAL COMBINATION
Sonic Frontiers has come through with two winners in Line 3 and Phono 1. Both units are cut from the same sonic cloth and are quieter than any other tube unit I've heard, transparent, fast and detailed. Best of all, the Phono 1 is compatible with even the lowest-output moving coil cartridges. Whether you listen to digital, analog or both (like I do), this combination will allow you to hear and appreciate your treasured recordings like never before.

Sonic Frontiers Phono 1 Phono Stage, Sonic Frontiers, 3535 Laird Rd., Unit #16, Mississauga, Ontario L5L 5Y7, Canada. Tel: (905) 828-4575. Website: www.sonicfrontiers.com. Designer: Sonic Frontiers design team lead by Mike Kerster. Unit comes with one of three gain options: 62 dB (O.6 mV output), 54 dB (I.7 mV output) or 44 dB (5 mV output). Price: $1,995.*

THOR AUDIO PHONO-BURN
This review was made far easier by this wonderful new accessory from Thor Audio. The Phono-Burn takes the signal from a digital processor and converts it into a reverse RIAA signal at a much reduced level. The unit also comes with a special disc from Purist Audio though for my purposes, I chose to use an ordinary disc. Using the Phono-Burn, you can burn in a phono section in slightly less than a week (assuming that, on average, burning in electronics requires 150 hours). It doesn't take a rocket scientist to figure out that with normal listening habits, it would have taken about 1 to 2 months to completely break in the phono section.

At first glance, the Thor Phono-Burn market seems restricted to reviewers (!), groups of audiophiles or possibly stores renting the unit out to customers buying phono sections. But another use for the Phono-Burn would be to warm up the phono section before playing each day. As we've all experienced, it takes the phono section, neglecting the effect of the cartridge loosening up, roughly an hour to warm up. Plug in the Phono-Burn, have dinner and the system would be ready to swing.

WHICH AC CORD?
The Phono 1 was auditioned with its stock and Synergistic Research's highly touted AC power cord. For whatever reason (and I feel that swapping AC cords is a crapshoot, at best), the sound of the Phono 1 with its stock AC cord was preferable to that when used with the Synergistic cables. The replacement cord was a touch quieter but produced a recession of the midrange, loss of body of instruments, some dynamic compression in the midbass area and a reduction of ambient space. This, of course, doesn't mean that another cord won't improve the sound of the Phono 1.

CARTRIDGE LOADING FACILITIES
Sonic Frontiers cites the ability to easily adjust loading value for any MC/MM cartridge. In reality, other phono sections offer more flexibililty; as reviewed, the Phono 1 comes with a default setting of 47,000 ohms in addition to settings of 100, 1,000 and 10,000 ohms. I would definitely like to see Sonic Frontiers equip the Phono 1 with more resistive loading values. That said, the optimal setting for the Parnassus D.C.t. cartridge was 47,000 ohms.

CIRCUIT DESIGN
The Phono 1 uses much of the same technology developed and employed in the Line 3. Critical parts are located on a separate isolated and damped circuit boards. The unit's chassis is damped with Soundcoat. An internally shielded, toroidal power transformer, especially designed for low noise and hum, is used in the Phono 1.

This version of the Phono 1 has 62 db of gain; other versions are available for higher-output cartridges. This makes the Phono 1 capable of amplifying the output of the lowest moving-coil cartridge without compromise. The Phono 1 is actually a hybrid design: The first stage consists of a single J-FET for the input amplifier and a 6922 tube with a special series amplifier for second gain stage; a second 6922 is used as a cathode follower after the second gain stage to reduce output impedance. The phono section is noninverting. A muting switch reduces the signal by 9 db.