AOM Logo July 1999


The Sonic Frontiers Power 1 Stereo Amplifier

Anthony Kershaw

A lot of water has passed under the bridge at Canada's Sonic Frontiers, from the humble beginnings of founder Chris Johnson's homebuilt preamp to an international company boasting some of the most popular designs in tube audio. Unfortunately, the company has had to circumnavigate a few fast tides lately, but from a recent informal factory visit, the slightly revamped corporation still has a few tricks up its sleeve. "Good for them", I say, for Sonic Frontiers truly exemplifies what is right about the High-End - solid engineering, trustworthy products, with excellent service and warranties. It has been my experience that these tenets extend to many Sonic Frontiers' products, but none more than the Power Series of amplifiers. The Power 1, 2, and 3 (rated at 55, 110, and 220 Watts respectively) have been Sonic Frontiers' high-end amplification mainstays for over three years.

The Sonic Frontiers Power 1 Power Amplifier

Sonic Frontiers continue to package their products with a luxury commensurate with the equipment's performance. I picked up the unit from the factory, which is but a short drive from my home. Unpacking the heavy beast was a little tricky - just remember to bend your knees (the packing weight is fifty pounds and the dimensions of the amp are 15" W x 20" D x 9" H). The double box, always a nice touch, came with everything a tewbie newbie needs to get up and running quickly. A well-documented manual guides the way. The tubes are labeled clearly and installation was simple. Gloves are provided, too - no sticky fingers will soil the glass - which is another nice touch. A detachable power cord is provided; all auditioning was performed with the stock cord and tubes (the supplied two matched pairs of 6550C/KT88 power output tubes and six 6922 input/driver tubes from Sovtek did the job admirably). Sonic Frontiers suggests that retubing should cost less than US$300.00. For the more adventurous among you, I have heard mention that switching tubes to a more esoteric variety will yield even better sonic results.

The Power 1 boasts 55 Watts a side. This was certainly plenty of power for my efficient Gallo Nucleus Solo speakers (90dB/W/m). The amplifier drove the speaker to very high levels of sound, with the Power 1 rarely running out of steam. Clipping was gentle, even when faced with the new Reference Recordings CD of Leonard Bernstein's music (RR-87 CD). This new CD packs a huge punch. Tweeters beware. Woofers, too! At outlandish levels, the Power 1 clipped gently suggesting a little distortion but without leaping to its feet screaming.

The rear of the amp is an audiophile's delight. The panel supports any number of variables - a switch allows you to select between two sets of single-ended inputs (in or out of phase), balanced inputs, or mute. Parts of high quality are used throughout, with exceptional binding posts from Cardas. The nominal speaker load is factory set at 8 Ohms. I did have a chance to listen at length with the amp set at 8 Ohms, but later had the factory adjust it to 4 Ohms to match the load of the Gallo Nucleus Solo speakers (the amplifier sounded equally effortless from either its 4 or 8 Ohm taps).

Visually, I have always been attracted to Sonic Frontiers' house design. Their standard gold or black metal fascia sports sprung power and standby switches. Also, the body is chromed nicely, the transformers are encased in black, and the unit comes with a detachable, matte black tube cage. Like most tube amps, the Power 1 runs quite hot, but nothing too worrisome. As such, your air conditioning bill should not jump exponentially.

Associated Components

Analogue:VPI HW-19 MK- III/Audioquest PT6/Benz Micro Glider .88mV, Rega Planar 3/RB 300
Preamplifier: Audio Research SP9 Mk. II
Power Amplifiers: Atma-Sphere M-60 Mk. II Reference monoblocks, Sonic Frontiers Power 1, SimAudio Celeste Moon W-3.
Loudspeakers:Anthony Gallo Acoustics Nucleus Solo
Cables: Interconnects: Audioquest Emerald, Kimber PBJ, Wireworld Polaris III. Loudspeaker: van den Hul M.C. The Sky-Line Hybrid. Audioquest stock phono cable.
Accessories: Black Diamond Racing Cones (Nos. 3 and 4), LP#9 stylus cleaner, Target PSW1 wall shelf and Target stand, Seismic sink, BBC boards.

Oh, the sweet, sweet sound of tubes. This flowery description has been around forever, but with the almost immediate addendum describing woolly bass, maintenance problems, cost of retubing, etc. Fortunately, companies such as Sonic Frontiers, Audio Research, Lamm, and many others, have laid to rest the slings and arrows of such outrageous fortunes. The Power 1's bass was deep and accurate, showing no sign of diffuse character. A rich midrange and a clearly defined treble joined this wonderful characteristic. Yet, we tube lovers are stuck with one small chore - biasing. "What's biasing?" the tube ingenue might ask. Although this was my first foray into the valley of glow, I knew what, but not how! For you other initiates, the Sonic Frontiers' manual deftly says: "Bias voltage applied to the grids of the power tubes in the output stage should be checked from time to time (once a month) to keep these tubes operating at the optimum operating point. A properly biased power tube will have a longer, happier life." For your greater good, Sonic Frontiers' engineering has made this essential tube maintenance as simple as possible. Screws at the bottom of small holes adjacent to the six power tubes are adjusted by use of a thin, plastic, pencil-like device. Each bias pot takes but a gentle twist of the hand to keep the green light (under-biased) or red light (over-biased) off. When all the lights are out, the tubes are in the groove, five by five!

The happily biased tubes sang some very lovely tunes. Listening was 50/50 CD/LP, with the amp unconditioned (the juice from the local company is spectacularly stable). Both the LP and CD format came out winners under the amp's gentle care. Tube and solid state aficionados would appreciate the wide soundstage and rewarding depth that the amp displayed on many different albums. Symphonic spaces such as the great Boston and Chicago halls were given full account, making my work on pieces like Audiophilia's continuing survey of the Classic Records reissues very pleasurable. CDs as varied as the recently sanctified Naxos Vaughan-Williams Seventh Symphony (8.550737) and London's wonderful Great Opera Scenes (G2 55760), with Renée Fleming singing her heart out, enjoyed accurate portrayal of instrumental and vocal timbre; flutes were flutes and trumpets, trumpets - the latter instrument particularly difficult to recreate electronically. Coloration, a word that seems to conjure dread in audiophiles (and reviewers) was present, but only appeared as a very slight lack of clarity, diluting the music's purpose a little. This did not hinder enjoyment over the long-term and was only apparent when I compared it to some ultra expensive tube amps heard at this year's CES, and after some home time with Ralph Karsten's remarkable Atma-Sphere M-60 Mk.II Reference monoblock amplifiers.

However, what really sold me on the sound of this amplifier was an initial session (after significant break in) listening to a Decca Jubilee pressing of Tchaikovsky's Fifth Symphony, conducted by Lorin Maazel with the Vienna Philharmonic. This is a great performance with outstanding sound, even from the mid-price pressing. Early one morning, a sound caught my ear. A sound so soft, so beautiful, it startled me. Just after the melancholy clarinet introduction to the first movement, the exposition proper starts with a gentle string figure in compound time. Just a pianissimo vamp, really. As heard through several solid-state amps, each note was lovely, tuneful, and just as it might be. Yet, the Power 1 dug deep below the surface of the sound and revealed the resin and vibrato intact. Fingers on strings remained, and it sounded so very real. This was one of those personal audiophile (and musical) moments that we treasure. It was this experience and others like it that convinced me of the refinement of the Power 1 and its ability to get to the heart of the music.

Recently, I have been listening to some wonderful piano CDs, these by way of recommendations from Usenet's rec.music.classical.recordings. The gentle folk (and some not so gentle) on this newsgroup offer detailed descriptions born of insight, intellect, and a true love of classical music. One recent rave was for a DG recording (459 634-2) of Russian virtuoso, Mikhail Pletnev. In Hommage à Rachmaninov, Pletnev records favourites of Rachmaninov, performs them on the composer's Steinway, and is recorded in the Rachmaninov villa in Lucerne. DG offers a wonderful sound, clear and bell-like, capturing a glorious tone from the famous piano. Moreover, Pletnev's touch is more languorous than clangorous, not always the case with many famous latter-day pianists. The Power 1 made easy going of this recording and other piano CDs, although the wide dispersion of the Gallo speakers made pinpoint imaging difficult. Component combinations that can produce a specific keyboard image are to be savored, seemingly still a difficult proposition for the high-end. Interestingly, the Power 1 did add a lovely bloom to some historical recordings that sounded downright harsh through other amps we have had in-house. With the lovely sounds still fresh, I would like to recommend any recording by the Russian pianist, Vladimir Sofronitsky. His is a unique genius; wonderful interpretations, gorgeous touch and tone, and always making the listener think about line and phrase. A Talents of Russia CD (RCD 16288) bears testament to his gift. Constricted historical sound this CD may contain, but the Sonic Frontiers' lovely demeanor shone light and reflected shade through these magnificent performances of Beethoven, Schubert, and Chopin.

The sound of these and many more intriguing CDs passed through the glow of the tubes of the Power 1. It can handle the most demanding source material (unsure, though, how it would fare with some of these sources on an inefficient speaker). And it swings and rocks, too. From its debut in my listening room nearly a year ago, it has given stellar service, bulletproof efficiency, and, most important, countless hours of musical pleasure. Therefore, it is with some regret that the sad day looms when it leaves for its birthplace.

At over threeyears old, the Sonic Frontiers Power 1 maybe somewhat long in the tooth in audiophile chronology, but it still offers present-day superior sound and a significant bang for the buck. In this age of high-end amplifier production overload, the ease of use, lovely tube sound, excellent engineering, and superb customer service, makes the Power 1 an easy choice for audition contender. Your time will be spent in the company of musicians not electronics, always the highest compliment I can give a product.

Power 1 Stereo Power Amplifier
Manufactured by Sonic Frontiers International
2790 Brighton Road, Oakville, Ontario, Canada, L6H 5T4
phone: (905) 829-3838, fax: (905) 829-3033
web: http://www.sonicfrontiers.com, e-mail: SFI@sonicfrontiers.com
Price: US$2499.00
Source of review sample: Manufacturer Loan
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