PLINIUS SA-102 POWER AMPLIFIER 'SAM'S SPACE!' By Sam Tellig.
 "But I have to say that I like the way that a solidstate amplifier controls a loudspeaker. And you know, Sam, solid-state amplifiers can sound very refined these days." So said Franco Serblin, of Sonus Faber, when I talked with him at the TOP Audio Video Show in Milan last fall. Back home, for my January column, I auditioned the Sonus Faber Cremona speaker with the Musical Fidelity A32 preamplifier and A32 power amp combination, and the YBA Integré Passion and the Unison Research Unico integrated amplifiers. But I wondered what the Cremonas would do with a BIG amp. (Franco himself tends to favor Krell.) As luck would have it, Vince Galbo,of Advanced Audio Technologies, called and offered a Plinius SA-102 power amp for review. "Ew." I told myself, having just returned from my weekly Italian lesson. "This might be perhto". A few days later, Vince came by with the amp. After a few minutes of listening, he shook his head. "You don't have a dedicated line, do you? Actually, I know the answer. I could see the lights dim when I turned it on." "Ahem... no." "To hear what this amplifier can really do, you should have one. Where does the power come into the house?" "Right under the living room." "Perhto," said Vince. "Videamo (Let's take a look)." Vince offered to install the line himself, no charge. I couldn't accept. "I have a plan." he declared after surveying the situation. "You buy the materials, and next time I come by I'll show you how it's done." I hesitated. "I insist. As the importer, I want the amplifier to perform at its best while under review." For years, my late friend Lars was on my case to install a dedicated line. I hope he has one now, wherever he is. Installation was a breeze, as Vince said it would be - but not a job for the inexperienced or the unsupervised. In a little more than an hour, the Plinius SA-102 was able to slurp juice from its own straw. There was nothing else on the line, not even other stereo equipment. (We used a PS Audio Power Port for the dedicated line's outlet.) Plinius wouldn't approve, though: they recommend running the whole system on the same line to minimize noise. I was surprised by the difference the AC line made. As Gertrude Stein liked to say, "a difference that's no difference is no difference?' This difference was a difference. I heard the improvement not only with the Plinius, but with every amplifier. The YBA Integré Passion and Unison Research Unico sounded more dynamic, smoother, cleaner. It takes two people to lift and move a Plinius SA-102. This is one big, serious amp: 18" wide by 8" high by 13 1/2" deep. It weighs 83 lbs. The heatsinks are humungous, as they need to be: most people will run the amplifier in class-A for much of the time, and they have to dissipate heat. The SA-102 can run in class-A or class-A/B. Either way, it's rated to deliver 14OWpc into 8 ohms and 22OWpc into 4 ohms. The amp can be had in your choice of black or silver-anodized aluminum. The price is $4995 - made possible, in part, by the New Zealand dollar, which I last saw trading for US $0.52. Like other amps in Plinius' SA series, the '102 doesn't skimp on build quality. The internal silver wiring is by Siltech. The speaker binding posts are very high quality-two per channel for biwiring -are by WBT. Inside, the amplifier looks built to a very high standard. The owner can configure the SA-102 to be a stereo amp, a bridged mono amp, or, using XLR connectors, a fully balanced monoblock. Operation is straightforward. When you turn on the amp, it defaults to class A/B with the speaker outputs muted. To get sound, flip down the lever to the left of the power switch. To cook in class-A, flip down the lever to the right. I use my right big toe (I'd plopped the Plinius on the floor; but, as with any amplifier, don't place the SA-102 directly on acarpet. I used apiece of wood as a platform.). "Is that amplifier staying on the livingroom floor?" asked my wife, Marina. "For the time being, yes?" Marina does make sacrifices. Once you flip the amp into class-A, it stays there for as long as you play music. But if the music goes silent for more than 30 minutes, the amp revertsto class-NB, saving you money on your electric bill. The amp really cooks in class-A, but runs cool as a cucumber in class-A/ B, thanks to the massive heatsinks. The SA-102 requires a mere 800mV input to deliver its full rated power output, making it a better match than most amps for a so-called "passive" preamp. Being (at Marina's behest) more active these days, I opted for Musical Fidelity's A3 2C R preamplifier. The CD/ SACD player was a Sony SCD-XA777E5. For analog, I used my Rega P25 turntable with Goldring G 1042 moving-magnet cartridge. Plinius Audio products have been available in the US for 10 years. But the company traces its beginnings to 1980, when Peter Thomson founded it, in New Zealand. As Pete once told me, that took pluck: there are more sheep than people in his country. A New Zealand hi-fi manufacturer must export. In 1987, Pete joined forces with Gary Morison to form Audible Technologies. Plinius is the company's brand. The company exports all over the world. In my November 1998 column (Vo121 N o.11), I reviewed the Plinius SA-50 MkIII, which sold for $2995. It was a honey of a SOW pc stereo amp. But audiophiles are.. well, sheep... and want lOOWpc or more. The SA-50 was eventually discontinued. When I wrote this month's column, it was Christmas season - summer in New Zealand. Christmas is their Fourth of July, as it were. Unfortunately, Pete Thomson was down with the flu, so I corresponded, by e-mail, with Gary Morison,the company's technical director. Plinius has a distinctive house sound, as I noted when I reviewed the SA-50. They achieve that sound, in part,by using only NPN output transistors, no PNPs. Output transistors come in two flavors: NPN and PNP. But, as Pete told me when I reviewed the SA-50, "the NPN transistor is a lot more linear and better-sounding than its PNP counterpart: In most solid-state amplifiers, an NPN is matched with a PNP to form a mirror-imaged pair of output devices. The Plinius approach is to match NPN with NPN - the SA-102 has three pairs of NPN/NPN output transistors per channel. The result is an asymmetrical deign, an output stage that's more push than pull. As Pete told me, this emulates the way sound behaves in nature - that is, in air. In an NPN device current flows one direction; while in a PNP device, current flows the other way. I asked Gary how Plinius matches the devices. "How do you make it work? Are the laws of physics reversed Down Under?" Gary was having none of that; but he was reluctant to describe how the devices are matched - afraid, perhaps, that someone will knock off his engineering. "Suffice it to say, there are a number of ways you can use NPN devices alone." Gary offered, sheepishly and perhaps a little stiffly. "We use one which allows reasonable efficiency." NPNs aside, Gary was forthcoming - and, like many electronics engineers, eager to teach. He reminded me of Paul McGowan, of PS Audio, or Leopoldo Rossetto,of Unison Research. Here's what he told me. "In the simplest sense [ie, mine], an amplifier is a device that takes a small signal and makes it bigger. Every gain stage in an amp or preamp attempts to do this. Ideally, the amplification of the signal produces an exact replica of the input signal, only a larger and more powerful one. "You've heard the cliché 'straight wire with gain'." It's often rolled out to describe the perfect amplifier." Gary continued, warming up - like a Plinius amp in class-A. "In the real world, however, no amplifying device -tube, FET, or bipolar transistor - scales the signal perfectly. All have nonlinearities. "An ideal device would have a transfer characteristic that is a straight line - the graph of the output signal would match that of the input signal. But all real-world devices have transfer characteristics that have some form of nonlinearity." So a designer's task is to uncoil the kinks, as it were? "In all Plinius products, we've adopted an asymmetrical topology." Gary continued, reinforcing what Pete had told me earlier. "This allows the music to come alive." "Yeah, like in single-ended triode?" I shot back via e-mail. "It's interesting that single-ended triode amps have found such favor. They have the same asymmetrical characteristic as our amps, but with much lower power and higher distortion." "Why do you use class-A when it seems so inefficient?" "We've found that biasing the output stage in class-A reduces nonlinearity. In addition, class-A operation ensures that the large output-stage current draw from the power supply remains constant, and this reduces power-supply modulation." Or, in plain English, there's inherently lower distortion in class-A operation. "And the result?" "Pinpoint images. Tonal clarification." Gary was almost gushing. "Inter-transient silence. More defined dynamic shadings. Inner detail and authority." Resuming his scientific demeanor, Gary expanded on the benefits of class-A operation. "With class-A circuit topology, the total current that the amplifier is capable of delivering is kept flowing in the circuit, regardless of demand while in a class-A/ B amplifier, current flow varies with demand. As current varies, the voltage on the rails as seen by the output stage varies too. This leads to the power-supply modulation common in class-A/B designs?" High-current capability is desirable in an amplifier and a major reason why many audiophiles favor big solid-state amps. (Tube amps tend to do less well when it comes to sourcing current.) Vince Galbo told me that you can almost determine an amplifier's current capability by its weight: the heftier the amp, the bigger its power supply and transformers, and the more current it can supply. "That's important in musical terms." Vince said. "When an amplifier isn't able to keep up with current demands, voltage sags and music suffers. You can hear it when a sudden drum beat comes along. If you don't have enough current, voltage falls down and the drum beat loses its impact." I certainly heard the kickdrum's impact on "Burning Love." on Elvis: 30 #1 hits (RCA 07863 68079-2). Other amps in house did deliver the same impact as did the Plinius. If memory serves me right, the SA50 MkJII sounded noticeably better in class-A than in class-A/ B, where the amp seemed slightly cold or sterile by comparison. The SA-102 was different. I often had to look at the class-A LED (to the right of the On/ Off switch) to see whether the amplifier was in class-A or not. Often it was working in A/B. I often doze off in the evening. By the time I wake, the SA-102 has reverted to class-A/B. "Drat!" I declare, puffing myself up from my listening chair. I posed the question to Gary. "Why does class-A/B now sound very close to class-A?" "It's because we have a very-largecapacity power supply." Gary replied from sheep country. "It's not easily modulated by output-stage current variations. And we still run a generous amount of output-stage current in class-A/B." So in class-A/B,the amp still operates in class-A - at least for a few watts. Some manufacturers of big solidstate amps have gone to sliding-bias arrangements in which class-A kicks in as needed, the amp stays cool, electricity is conserved, and so on. I call these things "miracle circuits." I asked Gary about them. "Any sort of sliding class-A bias - no matter how well it is done - will have a negative sonic impact. The scheme will cause some of the amplifier's operating parameters to be modulated by the signal - exactly what most designers want not to happen. "Sliding-bias schemes are usually used to reduce the large amount of heat generated in a class-A design. In the Plinius SA-102, we have enough heatsink area to dissipate heat without turning to compromises." I listened to the SA-102 for more than a month with the Sonus Faber Cremona speakers. I appreciated what Franco Serblin meant about "control." The Plinius SA-102 took charge of the speakers, especially the bottom end. I asked Gary whether this control came from a high damping factor. "While we achieve damping factors of around 50 or 60 into an 8 ohm load, we don't focus on damping factor as an overly important parameter. The amplifier has a massive, very-lowimpedance power supply, with high stored energy and high current capability. The output stage has such a huge capacity for current delivery that a woofer won't be starved, no matter how much current it needs." The treble was sweetly and smoothly extended. Franco Serblin was right: solid-state amplifiers have become very refined - some of them, anyway. With the Pliniu s-Cremona combination, I heard a lovely liquidity - a total absence of the hardness or harshness that, in the past,I've so often associated with solid-state. Two weeks before deadline, Renaud de Vergnette, of Triangle Electroacoustique, and Richard Kohiruss, of VMAX Services, his North American importer, arrived with the flagship Triangle Magellan speakers. These will likely retail in the US for around $35,000/pair. It's fun to go hors de ffltégrie, as the French hi-fi scribes like to say. Some of the Magellan's technology and magic will trickle down to more affordable Triangle models. And soon. When Renaud and Richard visited, we selected three SACDs: Berlioz's Symphonic Fantastique, with Paavo Järvi conducting the Cincinnati Symphony (Telarc SACD-60578); Rachmaninoff's Piano Concerto 3 and Scriabin Etudes with pianist Lang Lang, Yuri Temirkanov, and the St. Petersburg Phil- harmonic (Telarc SACD-60582); and Chet Baker's Chet (Riverside! Analogue Productions CAPJ 1135 SA. We rotated the three discs, comparing the Plinius SA-102 (with Musical Fidelity A3 2C R preamp) and two integrated amps: the Unison Research Unico and YBA Passion Integré. But after they left, I had another 10 days of listening on my own before deadline, and turned to non-audiophile material: Louis Armstrong in the 1920s and '30s. Ditto Duke. Count Basic's first recordings. The Chronological Bing Crosby on Jonzo Records. Iplayed many of the historical classical CDs that Klaus H eymann, of Naxos, has sent me: Jascha Heifetz, Yehudi Menuhin, Artur Schnabel. In many ways, vintage or "historical" recordings present the toughest challenge. Old recordings or new, the Plinius controlled the Triangles' multiple woofers with an iron grip. Despite their lack of dynamic range, many of these recordings sounded smooth, sweet, and mellow-not at all harsh or thin. Bass definition and extension were excellent. So was the overall resolution. I heard superb bottom-end control and a very sweet, smoothly extended midrange and treble. The Magellans are also capable of remarkable resolution, and the Plinius SA-102 did not disappoint. When I consider that these speakers retail for roughly seven times the amplifier's price, the latter's performance was exemplary. Someone buying an expensive speaker like the Magellan might allocate more than $5,000 for an amplifier. I wonder what two Plinius SA-102s might sound like. Bridge them into mono... or since the Magellan allows, leave the Plinius in stereo and simply biamp, horizontally or vertically. At a total price of $10 DUO, two Plinius SA-102s might make an attractive proposition, possibly gaining you a more expansive soundstage and an even greater sense of dynamic ease. There's something to be said for a big amp: it can make big sound. The Plinius SA-102 did this without ever turning hard or harsh, without sounding raucous or losing resolution and fine detail. This amp was as free of grain as any solid-state amplifier I have heard at any price. Was it perfect? Comparing the Plinius SA-102 to the YBA Integré Passion and Unison Research Unico, I had one slight reservation. Mind you, those relatively small integrated amps did not control the Magellans' woofers as well as the Plinius did, and didn't play as loud. When I tried cranking up the YBA Integré to Plinius levels, the amp blew a fuse. But I wonder whether the Plinius might have been a wee bit too polite. It's not that I heard any loss of resolution or detail - far from it. But I wanted Chet Baker's trumpet to be a bit more brassy, to have a bit more bite. Ditto with Paavo Järvi's recording of the Symphonic Fantastique. This piece can turn quite raucous, and Telarc's recording catches this aspect (accurately, in my view). With the Plinius SA-102, I felt that things were being smoothed over slightly, taming some of the music's bark, blare, and bite. (Gad, the music sounds like me.) I missed some of the vibrancy and life that I hear with great tube gear -that "lit from within" quality that I especially associate with single-ended triodes. I'm not sure what to call this, but I thought that the Plinius - at least with the Cremona and Magellan speakers lacked some degree of harmonic immediacy, leaving me sometimes less than fully engaged by the music. But how much would I have to pay to get that harmonic immediacy and the Plinius's bottom-end control? I suspect a great deal more than $5000. Let's say you bought a tube amplifier for roughly the same price. In the words of my colleague John Marks - a big Plinius fan - would a tube amp "wrestle the woofer to the ground"? And system matching is everything. Sonus Faber speakers are all noted for having the company's unique sonic signature - never harsh, possibly a little soft in the upper midrange and treble. Triangle's Magellan seems to mark a departure for that company, especially in the treble region, where there was a smoothness, sweetness, and refinement I had not heard before from Triangle designs. Neither speaker could be called aggressive. The Plinius SA-102 may be just what you need to control your speakers and tame any tendency they might have toward aggressiveness. For $5000, you get superb performance, excellent build quality, and the smoothest midrange and treble this side of tubes. And a dedicated AC line? I can imagine Lars reading this column and saying, "I told you so." 1 In horizontal biamping, one amp drives the midrange treble units, the other drives the woofers. In vertical biamping, a single amplifier drives a single speaker. You just have to feed the same signal to the inputs of both channels.
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