Sonic Frontiers Power 1 Stereo Amplifier

by Doug Schneider

Tubes. The way some audiophiles talk about tube-based audio gear you would think that their listening rooms are shrines where they pray to the great glass gods that bring them music. Come to think of it, I probably know some people who do just that! Then there are others who love having equipment that is designed in a way that shows off the tubes -- and as a result, they have something that looks so damn cool it will impress their friends.

However, not every tube lover is a fanatic or out to impress with a whiz-bang piece of gear. Rather, they are people who enjoy music and feel that the sound of a tube product brings them closer to the real sound of music. This is not confined to just the audiophile crowd; there are those in the professional circles of live and recorded music who feel the same about tube components. Warmth, richness, and harmonic correctness are some terms they use to describe the experience. Listen to some of the great tubes amps of today, and yesterday, and tube lovers could hardly be called wrong.

On the other hand, there are the solid-statesmen who figure that tubes are old school. They use words like slow, syrupy and bloated to describe toob-sound. They boast of near-perfect measurements, high power, bass that will knock your socks off and high frequencies that extend to the stratosphere as solid-state strong points. Furthermore, most solid-state amps require minimal, if any, maintenance, and will give years of trouble-free performance without the need to change output devices -- not a trivial point and not something tubes can boast about. Solid state defines the term plug 'n play.

Fences

While there are camps that pitch their tents on both sides of the fence, there are also a number of people who see the pros and cons of each technology and would rather let their ears dictate preferences for components. I like this approach because my own experience has shown me that you can achieve great sound with either technology. In my own system, I use the Blue Circle BC2 monoblocks -- a hybrid design that uses tubes and solid-state devices. I guess that confirms that I'm solidly...on the fence.

But this is OK because being in the middle puts the focus on the results achieved -- the bias toward the technology in use is eliminated. This approach has also worked successfully for me with endeavors outside of audio equipment. For example, I have found that I can listen to and enjoy both The Stones and The Beatles and avoid any need to choose which one is better. I can even place their CDs side by side in my music rack without a curse being put on my listening room. And when it comes to movies, I can be engrossed as easily as by Ang Lee as I can by Martin Scorcese, and I can watch something by Jane Campion on the same day I see a Quentin Tarantino flick. When it comes to comedy, I can laugh at Eddie Murphy as easily as Bill Cosby. To me, life is too short to obsess over principles for which there is no obvious right or wrong answer. Besides, why confine yourself?

Tradition

So when it comes to audio gear I try to eliminate any bias with a component (although I found with most tube gear I must at least adjust the tube bias. And with the Power series of amplifiers from Sonic Frontiers, this is done with a flick and a turn.) Writing this review today, I'm glad I have this attitude. After spending months with the new Sonic Frontiers Power 1 amplifier and its companion, the Line 1 linestage (review forthcoming), I can wholeheartedly say that these tube components do not sound like tubes at all - at least in the traditional sense. In fact, I would guess that people who listen to these components and wish to hear the expected tube characteristics will come away disappointed. But this does not mean that the Power 1 and Line 1 sound bad -- they don't. In fact, they sound very good. Furthermore, flick off the lights, cover up the glowing bulbs and I would guess that solid-state fans would have no idea they are listening to tubes -- and be quite content at that.

I've found that the Power 1 shares some of the best sonic attributes of tubes and solid state, combined with good reliability and ease of use. No, the Power 1 is not quite as simple to use as a solid-state amp, but it’s close enough that it tends to make the competition between the technologies almost irrelevant. Most importantly, the Power 1 doesn't have sonic characteristics that force a person to dwell on technology. Rather, the music becomes what matters.

3, 2, 1…

The Power 1 is the smallest of the Power-series siblings. There are also the 110W stereo Power 2 amp and 220W Power 3 monoblocks. All are push-pull units, a design philosophy Sonic Frontiers believes in, and all three amplifiers are based on similar circuit topologies. "Modern" tube design is how company president Chris Johnson proudly describes his offspring. The Power 1 is rated at 55Wpc, driven 20Hz to 20kHz, with an 8-ohm load. Although it can't be expected to drive the most difficult of speaker loads, it will easily drive a large number of speakers on the market, even those that dip down into 3- and 4-ohm territory.

In comparison to solid-state amplifiers that cost the same, the Power 1 delivers considerably less power. For example, you can expect a couple hundred solid-state watts for the same price. The question is, does that really matter? The real answer lies with the loudspeakers the amp will be used with, the size of listening room, and the preferences of the listener. A low-sensitivity loudspeaker that requires 100W before it plays to reasonable levels won't be a good match for something like the Power 1, particularly in a large room with a listener who enjoys LOUD music. However, for many reasonably efficient speakers, the Power 1 offers more than sufficient power. Over many months I used the Power 1, always with good results, with Speaker Art's Clef, Coincident's Super Conquest, Merlin's TSM and Gershman's new X-1 speakers. If you need more power, you can look to the Power 2.

To generate its 55Wpc of power, the Power 1 employs four 6550 tubes for output and six 6922s as input drivers. The tubes will require replacement over time and this will depend on your usage patterns. Average listeners can count on at least a couple years of play time from a set. When it comes time to re-tube, stock replacements from Sonic Frontiers will set you back $160 for the output tubes and $105 for the input units -- a fair price, I'd say, that should put aside most worries about ongoing costs.

For the course of the review I stuck with the stock supplied jobs. It's worth keeping in mind that with a tube amp, there is an ability to experiment with various types of tubes that can alter the sound, for the better and worse. There are numerous specialty retailers that can help in this regard, and if you need a bit of a primer, Sonic Frontiers packages their book, A Taste of Tubes, along with the amplifier.

From its appearance to its packaging to its overall presentation, the Power 1 is an extremely well thought-out, solidly built amplifier that looks great and is a snap to use. Parts and build quality of the amp are high, with a level of fit 'n finish that is very good. Speaker binding posts are from Cardas (which I find to be some of the best around) and are flanked to the side by a handy selector switch that allows choice of balanced input, two sets of single-ended inputs (one to invert phase), and muting of all inputs. On the front panel you find the power switch and a standby selector. Standby is used to keep the power amplifier's circuitry warmed up for short periods of time when you are not listening. The warranty is five years parts and labor on the amp and one year on the tubes.

Maintenance

One of my biggest worries with regard to tube components is one that many people share -- ease of use and maintenance. Sonic Frontiers has gone to great lengths to make their current batch of tube components user-friendly. The only thing that could be called a hassle with the Power 1 is the 20 minutes or so of initial unpacking and tube plug-in to set it up -- and even that's not too bad, particularly since it's a one-time chore. Sonic Frontiers could ship units with all the tubes in place; however, they would also be risking damage while in transit. Instead, you get to do the honor of final assembly, which is good experience anyway. The minimal number of tools necessary for the job, including spiffy white cotton gloves, are supplied.

Once the amp is set up, the only other regular maintenance required is to check the bias of the tubes to ensure that it is set to the optimal level. I checked the bias about once per week, although Sonic Frontiers says you can go much longer than that. It's a simple two-minute job that's made even easier with all the tubes, LED readouts, and knobs in easy-access positions. Each of the four output tubes must be biased separately. To bias a tube, you must simply lean over, watch the LEDs and turn one of four screws with a bright red stick. You know you've got it right if the LED adjacent to the tube turns green and doesn't go red. Done!

System

The Power 1 glowed warmly among my usual roster of gear. Up front and digital is the Theta Data Basic into a Prime II DAC intercepted midway by the Camelot Dragon Pro2 Mk2 digital processor. The Blue Circle BC3 preamplifier was used for the majority of the time with Sonic Frontiers' own Line 1 placed in the system for periods. Speakers, as mentioned, revolved around the Merlin TSM, Gershman Acoustics Avant Garde and the Speaker Art Clef. Wiring throughout was Nirvana Audio S-L series, and power conditioning came in the form of the Audio Power Industries Power Wedge 114, as well as Blue Circle Audio's Power Line Pillow.

Usage

When I first received the Power 1, I was completing my review of the Anthem Amp 1. Anthem is Sonic Frontiers’ lower-priced line aimed at audiophiles with budget constraints. The Amp 1 is an all-tube, 40Wpc design that packs tremendous value at $1299. At just under double the price, the Power 1 certainly looks nicer and is built to a much higher standard, but is it really worth the increase in price? Before the Amp 1 was boxed and shipped, I did side-by-side comparisons of it and the Power 1.

It wasn't surprising to find that both amps share some sonic similarities, particularly in regard to detail and neutrality. However, it didn't take long to figure out that the Power 1 was clearly better over most aspects of its performance. In comparison, the Amp 1 sounds a tad woolier, lacking the Power 1's tightness and control from the bass through the midrange. Furthermore, the bass is deeper through the Power 1, the highs more pristine, and the midrange has a notch more clarity. Retrieval of detail is comparable; however, the Power 1 shows better soundstage width and depth with better solidity of images within those boundaries. The differences do not diminish the Amp 1 at all because it represents outstanding value at its price. This is the type of amplifier that I wholeheartedly recommend for people whose budgets won't extend beyond. If one's budget allows, however, the Power 1's price is certainly justified, at least in this comparison.

What quickly won me over about the Power 1 is its sonic purity, retrieval of detail, excellent neutrality and see-through transparency that sounded nothing like traditional tube sound. This took me quite by surprise because I've listened to most of Sonic Frontiers’ previous series of amplifiers (the SFS-40, SFS-80, and SFM-160), and although those amps were good value in their day, they tended to sound darker, less transparent, and not as extended in the frequency extremes -- closer to tube sound stereotypes. They sounded pretty darn good, but they had a sound -- their own sound.

The Power 1 has the neutrality and transparency that solid-state amps are known for. There is no bloat, no exaggeration, no coloration -- just clean, clear music. The bass is strong and tight, and the highs are pristine and extended. Soundstage width and depth are completely natural and exhibit just what the recording offers. The Power 1 puts out what its fed -- no more, no less. As a reviewing tool, the Power 1 performs remarkably well, which cannot be said about all tube-amp designs. Its neutrality allows it to be matched with a wide range of components, and its neutral and revealing nature allows you to discern component changes in your system easily.

I used my Blue Circle BC3 and the Sonic Frontiers Line 1 line-stage preamps during various listening sessions. Each worked well, but yielded a different sonic result. The Blue Circle had a weightier sound, while the Line 1 was a little leaner with more high-frequency energy. I found that using the Nirvana Audio cables throughout my system yielded consistently excellent results and were my cables of choice. JPS and DH Labs interconnects were slid in for a time and both proved very good at a more cost-effective price. Audio Marginal's pure silver speaker and interconnect cables worked well, as did the outstanding, but difficult to find, pure-silver Temporalis interconnects.

In all, I found the Power 1 to be an exceedingly natural performer. However, I could imagine that some listeners, perhaps those looking for more traditional tube sound, will not be as satisfied. The Power 1 lacks the tubey warmth that other amplifiers, even Sonic Frontiers’ older models, are known for. While this is a plus in my books, it could be a minus in others.

Mo’ money

Seeing how the Power 1 would perform against a more expensive contender, I slid (literally) my Blue Circle BC2 monoblock amplifiers into the listening room. I fell in love with these large, esoteric, and crazy-hot amps from Innerkip, Ontario, Canada when I first reviewed them over a year ago -- and I now own a pair. Their performance is definitely top-class, and they are the most musically satisfying amplifiers I have used.

The differences in this mini-shootout? The BC2s exhibit a slightly sweeter top end with an ability to extract a tad more detail, particularly in the midrange. Soundstage specificity and the ability to portray depth were also improved through the BC2. The BC2s had a sense of ease and ultimate smoothness that the Power 1 just missed. All in all, the BC2s squeaked by the Power 1. However, the margin of improvement was not nearly the improvement gained going from the Amp 1 to the Power 1. Given the $6000 price tag for the Blue Circle amps, the $2499 Power 1 must be considered a bargain. If you don't have lots of extra cash to burn, don't sweat it. The Power 1 is a darn fine little amplifier!

Conclusion

I could not ask for more in a tube amplifier at the price of the Power 1. If I didn't love my Blue Circle BC2 monoblocks so much, I would have bought the Power 1 -- I think that highly of it. I feel it gives me almost everything I need in terms of sonic performance and is wrapped in an a well-designed, high-quality, no-hassle package. It's neutral and revealing in a way that a reviewer needs, while musically engaging to satisfy long-term listening habits. I am certainly won over by its price and performance. Don't buy your next amplifier without at least auditioning the Sonic Frontiers Power 1 -- it's a taste of modern-day tube sound.

...Doug Schneider
das@soundstage.com

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