Reviewer: John Potis
Digital source: Pioneer DV-535 DVD player and Bel Canto DAC2, McCormack UDP-1 Universal player [for review]
Analog Source: Sota Jewel, Sumiko Premier FT3, Micro Benz MC Silver
Preamp: Shindo Partager
Power Amp: Art Audio Carissa, Bryston 7B ST
Speakers: Silverline Sonata II, Ohm Acoustics Walsh 4 with 4.5.2 upgrade, Third Rethm [for review] Thiel PCS [for review], Axiom Acoustics M3ti, Velodyne SLP800
Cables: JPS Labs Superconductor interconnects and speaker wire, DH Labs D-75 digital interconnect, JPS Power AC, Analog AC, Digital AC and Kaptovator power cords
Powerline conditioning: Balanced Power Technology 3.5 Signature with Wattgate upgrades
Sundry accessories: Vibrapod Isolators and Cones, Ultra 1 ZSleeves
Room size: 12' by 16' with 9' ceiling. Speakers set up on long wall in quasi Audio Physic orientation
Review component retail: $5,000 with Sophia Audio 300Bs [$4500 in matte black with chrome or gold accents]

Recently, I was talking to a well-intentioned fellow reviewer (not a moonie) who was telling me about a very powerful, very expensive tube amplifier. "It sounds just like solid state!" he kept repeating as though this was the highest praise he could bestow.
So I asked him, "Okay, then tell me something: Who's going to buy a tube amplifier that sounds like a solid state amplifier?" He didn't seem to understand the question. Twice more he charged with the same battle cry: "It sounds just like solid state. It's the best amplifier I've ever had in my system!" So twice again I asked him who was going to buy an amplifier that used tubes requiring periodic replacement as well as periodic biasing and whose thermal output would promise to fight the A/C all summer long. If it really sounded like solid-state, why wouldn't someone just buy solid-state? Once he understood the question, he didn't have an answer while I wondered how the maker of his tube amp would react to such an - er, compliment.

It's true and I've even said it myself - the best solid-state and tube designs sound much more similar today than in the days of yore. Most of the stereotypical traits once associated with tubes such as weak or mushy bass, euphonically amber midranges and truncated highs are things of the past. But that doesn't mean that they sound the same, no sir. Nor should they.

No, just as with all other gear, when it comes to amplifiers I say "Vive la difference." Practical considerations aside for just a moment, wouldn't it be a bore if they all did sound the same? Simply close your eyes and pick an amplifier according to your power needs. Easy, right? Of course, there are practical considerations that make choosing from all the different designs and tubes both fun and necessary for a properly matched system. With tubes, you pick an amplifier for its particular output valve and how it is implemented for a sonic signature that compliments your system, your room and your tastes.

There's a bewildering selection of both tubes and amplifier circuits and while I've heard many, what I've heard accounts for only a tiny percentage of what's available. Still, I have my favorites. If you need 40 or more watts and midrange is your priority, nothing beats the EL34 output tube for my money. It's true, even as today's designs go, the EL34 is still a little ripe in the bass but not like they once were. If this is as bad as it gets, I'd survive. But if bass slam were your priority, there's the 6550 which, when properly implemented, can stand toe-to-toe with solid-state in both bass slam and treble extension. However, don't look for the same kind of velvety midrange you get with the EL34.

If you have a small room and/or efficient speakers and 40 watts seems like an extravagance, there's a whole subset of amplifiers you should look at: Single-ended triodes. These amplifiers will never sound like solid-state. If anything, one day, maybe, solid-state will sound like them. But these tubes will never aspire to duplicate the sand-amp experience.

Even this small subset of amplifiers has a wide array of tubes dedicated to the single-ended design approach. Art Audio alone uses tubes such as the PX-25, the 845, the T-100, the VHD 842, the 32B and the 52BX, among others. But perhaps none enjoys a more stellar reputation than the 300B tube employed in the Symphony II. And, no one claims any of them to sound like solid state. In fact, with the right speakers, some of these have been known to beat solid-state at its own game.

Nuts and Bolts
The Symphony II is a transformer-coupled pure class A triode stereo amplifier rated at 10wpc with the standard mesh-plate Sophia Audio 300B. Art Audio specifies a very high input sensitivity of 400 mV. Input impedance is 220 kohms and the Symphony II comes wired for either 8 or 4-ohm speakers (my sample came wired for 4 ohms). Art Audio specifies a frequency response of 20 to 20kHz at full rated power. The Symphony II weighs in at a hefty 65 lbs and measures 18.5 inches wide, 13 inches deep and 10 inches high at the transformers. Art Audio suggests compatibility with speakers of 90dB or higher.

The Art Audio Symphony II is a zero feedback amplifier, which, like all Art Audio designs, is said to possess high peak current delivery as well as automatic biasing circuitry via two distinct biasing circuits. Though it ships with the Sophia Audio 300B standard, the Symphony II will take any 300B tube extant. This includes the new KR Audio 300B, the Western Electric and Sylvania versions, the Valve Art 300B C60 and 6300B or other substitutes. My review sample came equipped with Western Electrics, a $500 option (the tubes list for $900/pr retail when purchased separately). Art Audio claims a true dual-mono design on a single chassis, high quality mil-spec multi-layered 2 oz. copper trace circuit boards, capacitors that are low ESR/ESL types said to increase high-frequency performance and resistors that are 1% metal oxide variants for low noise. Tube rectification is via the Valve Art 274B (standard) or the Sophia Audio 274B (optional). The remainder of the tube complement includes two each of the 6922/6DJ8 and 12BH7.

Art Audio's Joe Fratus told me that the primary reason for the Symphony II sounding the way it does is due to its use of the tube-specific, hand-wound split-core output transformers. To his knowledge, these transformers have never before been used in 300B amplifiers. It took his firm 3 years of research to adapt this transformer design to the 300B tube. The result is said to be complete frequency extension in both bass and treble. In fact, Fratus explained that
the Symphony II's frequency response is 18 to 60 kHz at +/- 3 dB and with less than 1% distortion. In other words, 300B sonics marked by weak bass and rolled-off highs are now a thing of the past. Well, at Art Audio anyway. Joe Fratus explained further that a higher-than-usual damping factor is another key performance parameter that differentiates the Symphony II from the pack. He added that superior output transformers and a hefty power supply are other key ingredients. Lastly, the Symphony II uses all tube rectification eschewing silicon diodes used in other designs. Standard finish is polished non-magnetic stainless steel with chrome or gold accents. A satin black finish with chrome/gold-plated accents is available for $500 less.

The Many Faces Of Art Audio
Some manufacturers seem to strive for their amplifiers to differ merely in power output and price but otherwise sound the same. Conversely, Art Audio seems to enjoy taking a tube and designing an amplifier around it that showcases what that particular tube does best. Then the designers set out to attack what is often considered their tube's weaker performance parameters in order to improve upon them. In the case of the Carissa I reviewed and subsequently purchased, they focused on the economical 845 which is prized for its power output, dependability and midrange transparency but less so for its bass prowess and treble extension. The 845 is known as a midrange champ but that's not what Art Audio brought forth with the Carissa - a spirited, powerful and wide-bandwidth amplifier.

Prior to the Symphony II's arrival and where the venerable 300B is concerned, my most memorable up-close-and-personal experience had come with the Opera Audio Reference 9.9C mono amplifier I reviewed for SoundStage!. I don't have to go back and re-read that review to refresh my memory. I was mightily impressed by the Opera. It had midrange purity so colorless, so musically detailed and so focused that it brought me closer to the concert hall than anything else I had ever heard. I didn't fault the amplifier then and I don't fault it now because it was just an issue of system matching - but what stood between my buying the amps and sending them back was the fact that the amps lacked the body and warmth that better would have suited my system at the time. The amps just didn't have the cozy warmth that would have resulted in the kind of synergy from which I wouldn't have been able to walk away. Alas, the Art Audio Symphony II does.