Review: Plinius SA-102 power amp

Category: Amplifiers

Plinius SA - 102 Power Amplifier

I was first exposed to the Plinius SA-100 Mk. II in 1997 after reading a review wrote by Wes Phillips in Stereophile Vol. 20, No.4. I bought one in the fall of ‘97 after auditioning it against the Mark Levinson 331, Pass Alpha 3, Jeff Rowland Model 2, Bryston 7B, Krell FPB-300, Ayre V-1, Sonic Frontiers #2, Audio Research VT 130SE, BAT VK-60 and Cary CAD-805 . The Plinius SA-100 was 100 watts at 8 ohm (360 watts bridged mono) Pure class A. This amp possessed a wonderfully warm tube like midrange, smooth highs and solid bass. I found it extremely detailed with excellent imaging and a good deep sound stage. I loved the sound, but had a series of problems. The mute switch created a pop sound when switched on or off. The Plinius SA-100 had ground loop hum issues, nothing I was not able to solve, but every time I would change anything in my system I would have to rework the grounding to solve the hum. This amp finally died with a cloud of white smoke and an awful electrical smell. This was the end of round one for Plinius and me.
I moved onto a pair of Aloia Inductive power amps. These amps had all the virtues of the Plinius in midrange and the high end. The bass was less impressive on the Aloia but not so much that I missed the Plinius. Imaging of the Aloia was good but not nearly as pinpoint or etched as with the Plinius. December 2001 a friend brought me a new Plinius SA-100 to try. This was one of the last model SA-100's made. I found the same popping at the mute switch and the same ground loop problems existed as they had three years earlier. What I also found is that I missed the Plinius's imaging and slam. I ordered two of the new model SA-102, and waited a month and a half before they arrived from New Zealand. Finally two massive 90 lbs. boxes arrived at my door. Wasting no time opening the boxes I set the two amps in the middle of the floor, they were beautiful black anodized aluminum. Plinius have not changed the looks from the SA-100. These are very seductive amps. Each amp has the same massive aluminum handles smoothly built into the thick aluminum faceplate. The same cut out in the lower middle of the faceplate has the same two toggle switches and the main power rocker switch as the model had before. The very elaborate cooling fins on the side are again the same as before along with the rear panel. Two sets of very well built five way binding posts are situated with plenty of room for hooking up even the fattest cables. Both RCA and XLR inputs are available with a selector switch that allows the user to set the amp up for RCA stereo or mono-bridged and XLR stereo or mono-bridged. The SA-102 is now 125 watts at 8 ohms pure class A in stereo and 460 watts at 8 ohms pure class A in bridged mono configuration. The new amp is 8 3/4" h x 19 3/4"w x 18" d, 83 lbs. Where the old was 8 7/8" h x 18 3/8" w x 13 ½" d, 70 lbs. After reconfiguring my rack system I set the amps up and plugged these bad boys in to see how they worked.

Set-up

An initial set-up of the amps was in a bridged mono block configuration using the XLR inputs. I chose to burn the amps in this way, thinking they might be broken-in faster with the larger wattage. I have no idea wether this is true, but that is how I did it. After a week of playing the system during the day while listening at night, I switched the amps over to RCA inputs for two more weeks of burn-in. They now were set in stereo mode, bi-amped in a vertical configuration. I had a few minor problems arise, either through operator error or the amp not understanding they had switched it to RCA stereo. It blew an internal rail fuse found inside the amp, under the top panel. Of course this now gave me the excuse to open the top and look around. Four internal fuses are found on the main circuit board, each with a LED light next to it. If the fuse does blow, the LED lights to show the fuse that blew. I replaced the 10 amp normal blow fuse and turned the system back on. It blew again so I went back and reconnected everything. Unplugged the amps and pre-amp power in case some memory chip was trying to tell the amp of the earlier setting for XLR. Whatever I did it solved the problem, I now had RCA vertical bi-amps. While I had access to the main circuit board, I could find a few of the new features. The first is an eco logic Control. This allows the user to set a time for the amp to switch from Class A automatically to Class A/B if the amp is left with no signal to it. The benefit of this is that in Class A, the amp draws 500 watts in idle, in A/B it is around 35 watts according to my meter measurement. The eco logic control allows for select times of 15, 30, 60 minutes or turns the option off completely, it is set at the factory at 30 minutes. The SA-100 did not have this feature and it drew 1000 watts in idle. Therefore if I forget to switch it back to A/B, it burned quite a bit of electricity and staying very hot. Another new feature is a LED brightness control. Again this is on the main circuit board and allows the owner to dim or brighten the LEDs on the front panel. I counted ten Bi-polar output devices (bolted directly to the heat sinks). I do not know how many were in the original, but ten lined up is very impressive. Another major change from the SA-100 is in the power supply. I did not remove the bottom panel to get a first hand look, but there is a good picture at the Plinius web site www.pliniusaudio.com. Where the SA-100 had one main transformer, the SA-102 has dual toroidal power transformers ( aprox. 8" dia.) with much higher capacity than those in the SA-100, improved power supply filtering, circuit refinements, and the same energy saving and error detecting logic control as found in the SA-250. Just a couple other items worth noting before I move on. The pop I referred to on the mute switch of the SA-100, it has gone. Whether this is because they changed the circuit or simply abandon the toggle switch of the SA-100 and replaced it with a pulse switch (that looks just like the toggle) I am not sure, but there are no pops! The ground loop hum was also gone with the SA-102, again the reasons I do not know but I appreciate having those two concerns dealt within a positive way.

The Sound

So how does one describe perfection? I guess I could simply say this is the best amp I have ever heard and leave it at that. Instead I will try to give some idea of what I heard. I guess to start I would say the overall sound is extremely natural. The pace and dynamics are flawless. A friend described the sound as warm, but not artificially so in the mid range. Female vocals sound real and natural with no excess of glow or color. The bass is tight, dynamic and focused with no wooly blooming or exaggerated depth. Sound stage was huge, both in width and in depth. The feeling of the acoustic space is very prevalent in all recordings, both in the overall venue and between instruments. However, it is the transparent high frequency that most impressed with, and that is how I will start.
Piano, violin, piccolo, organ and soprano vocals can be the toughest instruments to reproduce accurately, at least with the systems I have had. Piano is notorious for sounding electrical and artificial in the top octave. Plinius have gotten this right. Even the highest keys of the piano sound like a string being hit, and then a tone vibration into decay. Each string has a precise timbre when struck, followed by a full pallet of colors. I liken it to watercolor painting. If a painter starts with a brush stroke in the middle of a white sheet of paper and continues to wash that first stroke down the paper with water, the result will be a fine line where they took the first stoke. Continuing the wash decreases the color until almost transparent but always with some original tinge left. With the Plinius SA-102 the piano key hitting even the shortest string begins with a sharp point of color, fading off into several subtle shades and hues of the original color. I found myself seeking out recordings that I always found fatiguing and tiring to which to listen. After six hours of what I have always considered bright and edgy recordings, I was not in the least fatigued from the sound. I found myself excited with how smoothly this amp handled this difficult presentation. Now I am not claiming this amp will take a bad recording and magically make it good. I am referring to well-recorded pieces that comprise of a great deal of high frequency energy.

Percussions

Cymbals have always been a source of interesting texture and sounds. Now all these sounds have exquisite tonal coloring and a delicate richness in their hues. Cymbals now begin with the impact of the drummer's stick followed by countless hues of shimmering tones and glistening color. The entire cymbal becomes defined by these shimmering sounds. Not only is the point of where the stick touches the surface of the cymbal defined, but the entire diameter of the cymbal itself is easy to see. Drums are even more impressive. As the drum is struck, the subtle tonal differences from one tap to the next are delightfully presented. The dynamics and transient attack is exhilarating, timing and pace is perfect. The entire face of the drum becomes apparent along with its location in the sound stage. Bass impact is stunning, playing the Reference Recordings of the Minnesota Orchestra is a great tool for me to use for determining the effect of the kettle drum. I have been to several presentations in person, my knowledge of how a kettle drum affects Orchestra Hall and how the dynamics compare to the rest of the orchestra is something I am intimately aware. This Plinius could produce the full Dynamic impact to a tee, and the reverberation and decay is flawless. This is the first time I have felt a stereo system that was completely able to reproduce the proper scale of Orchestra Hall accurately. On Patricia Barber's Modern Cool the percussions consist of two members. One drum set and one on bongos among other instruments. They define the face of the bongo skin along with the height of the drum's cylinder. It is a wonderful experience to sense such detail. I think it is important to explain that although the detail is extremely well defined, never overly etched or artificial in its feel. One minor complaint I had with the SA-100 was the detail was at times overemphasized. It created the illusion of a computer-enhanced photograph. The focus was sometimes simply too tight, too defined, almost like a cartoon where they outline the figure with a pen, rather than a natural edge to the picture. The Plinius SA-102 has refined this fault. Never did I feel the picture was unnaturally focused. It was simply a photo made with the best Nikon lens, but never enhanced in an artificial way.

Midrange

O.K. your saying, but what about the midrange? I hope I have made it clear that the bass and treble are as good as I have ever heard, but it is the midrange to which we all listen. I listen to jazz and rock female vocals at least 50% of the time. For me the midrange is the most important. Well, the Plinius did not let me down. I have heard so many amps that simply tries too hard to sooth me into loving them with unnatural glowing midrange, often sounding thick and muddled. Again the Plinius was not one of those. The midrange is extremely natural, rich and warm, but not so colored that I felt like melting. Plinius were simply right, if the voice is liquid, glowing warm or whatever the adjective, the Plinius reproduced it accurately. Most vocals are not quite so perfectly radiating however, it is the subtle harshness of the upper throat and vibrating of vocal cords that produce the emotion and character. Too often amps try so hard to please with their synthetic midrange that the actual character and emotion of the voice are lost. Not with the Plinius, here the warmth is euphoric if the recorded voice possesses euphoria. As a singer voices from the throat to the chest, the glow intensifies. The depth of color available within the palate is again endless. Much like your computer has "Millions of colors" this has Billions. I found myself completely entranced, fully engulfed in the experience. I could almost feel the singers soul as she sang, it was truly as if she were in the room, so palpably real. When listening to acoustic guitar or other string instruments the glow and shimmer of the strings sang out. Rich and deep, the experience is like being in the best venue with the front center seat. Again, I have heard warmer, fatter, thicker midrange reproduction, but they feel muddy and blurred when compared with the natural atmosphere of the Plinius.
So by now it is obvious I think this is a superb amp that produces great detail and wonderful imaging. The true grace of this amp is it can put all this detail into a natural tapestry of sound. Although the amp can precisely place an instrument on the sound stage with great air and space around it, never was it distracting or overemphasized. Generally the presentation is fully integrated in the same way that a patch work quilt combines many separate textures and designs into a single beautiful composition. Most of the time it was the overall presentation I enjoyed. If I wanted to focus on one instrument within the sound stage, doing it was easy and natural. As with an orchestra, the full ensemble is the picture, yet each section, and for that matter each instrument, has space it occupies. All these details make up the picture we see. With orchestras the individual instruments should remain visible even during the most complex passage. Often amps fail to retain this detail fully. The Plinius never faltered, even during the loudest, most complex sections of a symphony the detail remained transparent and clear. The kettle drum never became muddy or washed out, the strings remained transparent with a glorious glow of color, brass was sharp and textured. Timing and pace remained quick and precise, dynamics were distinct with a leading edge to each note and each instrument always presented with the right speed and impact.

The Plinius SA-102 carries all the transparency of the Pass Aleph 0 and 3, the quickness and impact of the Levinson and Krell, smooth liquidity of a Rowland, the lush midrange of a Bel Canto and the airy texture of a Cary single ended. What is so amazing it is all in a single amp. In order for me to experience the most that the Plinius SA-102 can offer, I found I needed the cleanest transparent signal I could achieve. In my system the modified Sony SCD-1 with all Vishay resistors and Black Gate capacitors along with an upgraded opp amp and power supply is extremely transparent and open. The CD playback is virtually as good as the SACD playback, making it (in my opinion) one of the best digital systems available today. The Placette pre-amp also uses all Vishay resistors making the combination extremely clean and revealing. Using the Aloia, Theta or Kora pre-amps added a small amount of haze to the system, covering up some subtle hues and tones I found so special. In the same vane, interconnects and speaker cables other than the Valhalla were less involving, less inspiring. Overall the more transparent the system, the more through which the richness of the Plinius could shine.

The Plinius SA-102 has one fault. It runs very hot, in the same way any Class A or single-ended tube produce a great deal of heat, the Plinius becomes a 500 watt space heater. It is not so hot as to burn the skin, but it will require air conditioning in the warmer months. Luck for me, Minnesota produces 8 months of natural air conditioning, and as luck would have it the natural cooling comes during the longer, darker months. These also happen to be the best months to spend listening to the stereo.

Is this the best amp available? How the hell do I know. All the amps mentioned in this review, I have heard over the past couple years. For my taste, in my system the Plinius could match the attributes of each of these amps, and yet to my ears had none of their short comings. In my mind, this is the best I have ever heard, and must be among the best available. I realize this amp will not please every person and cover every desire a listener may have. Some people will always want something more that this amp could provide. If it is overly euphoric warmth that some tube amps offer, or a highly etched, extremely sharp image that some solid state amps provide, than the Plinius simply will not fit your needs. If your looking for a perfectly natural, extremely transparent, non fatiguing amp with extraordinary slam and dynamics I would suggest seeking this amp out. In my mind it is simply perfect.

Plinius SA-102 Specifications

125 watts RMS 20Hz to 20kHz into 8 ohms both channels driven
460 watts RMS 20Hz to 20kHz into 8 ohms bridged/balanced mono
Frequency response: 20Hz to 20kHz +/- 0.2dB, -3dB at 5Hz and -3dB at 70kHz
Distortion: typically <0.05% THD at rated power
Saturation:140 watts per channel or greater into 8 ohms, 220 watts into 4 ohms
Rise time: Typically 5us
Phase response +0 at 20 Hz and -14 at 20kHz
Hum and Noise: 100 dB below rated output 20Hz to 20kHz A-weighted
Input impedance: 46k Ohm
Input sensitivity: 0.8V RMS for rated output at 1kHz
Serial Numbers: 1040 and 104
Manufactures Recommended List Price: $5000

Musical selection

Too numerous to list, I played more than 60 CD and 20 SACD's during my review that lasted over a month. Selections included vocals, choir, symphony, concertos, jazz ensembles, big band, rock and roll, blues, acoustic, piano solos and raga.

System used

Digital: Sony SCD-1 with full Audiocom-UK modification (see review on Audiogon)
Pre-amp: Placette active solid state pre-amp
others
Aloia Inductive power
Kora Eclipse triode
Theta Casablanca
Amp: Plinius SA-100 MkII
Aloia Inductive power bi-amped vertically
Speakers: Dunlavy IVa with bases removed, supported with Black Diamond cones and pucks with Walker High Definition Links on all terminals
Power: Shunyata Hydra power conditioner
NBS Statement power cords
20 amp dedicated circuits with 8 ga wire and Hubble outlets
Quite line filters at noisiest outlets
Cables: Nordost Valhalla interconnects and speaker wire
others
NBS Statement interconnects
FIM Gold interconnects
Nordost Red Dawn speaker cable
NBS Statement speaker cable
Audio Tekne speaker cable
Misc. Apollo rigid steel rack
Neuance Alpha and Beta shelves with EAR footers under equipment
Numerous footers and cones
Walker resonance control disks
Misc, room acoustic devises

J.D. MacRae