Vitus Audio RI-100 Integrated Amplifier
Excellent condition with remote control and packaging
At its core, the RI-100 is essentially the Vitus Audio RS- 100 solid-state stereo amplifier with the addition of a linestage preamp. It outputs a stout 300Wpc RMS into 8 ohms. Cosmetics are minimalist but the amp is built to endure. It shares both the chassis and the massive aluminum faceplate and pushbutton controls of the RS; however, unlike the Signature and Masterpiece components, the rear casing is prosaic sheet metal, a nonmagnetic aluminum rather than the thick slabs of steel and aluminum of the pricier products. The expansive back panel houses a pair of unbalanced RCA and a trio of balanced XLR inputs, plus a preamp output.
Controls, memory functions, and assorted connectivity can all be optimized via menu-driven software from the front panel or remote control. The latter is an Apple remote, not the fullyfeatured rechargeable masterpiece that the uptown Signature Series offers. Since it’s an off-the-shelf device, the user needs to pair the remote to the RI-100 (unless you like triggering other Apple-compatible devices elsewhere in the house). Like the pricier models the precision volume control is relay-based and employs only a single resistor in series with the signal at any given time
I asked company president Hans Ole Vitus about the key differences between Reference RI-100 and the previously reviewed SIA-025. He stated that the output stage is identical to the SIA-025, but with some topology differences in the input module. The transformer is a more traditional EI-core rather than the Signature’s custom UI-core. Parts quality and matching of internal components, while stringent in the Reference Series, reaches an ever-higher threshold in the fully balanced Signature Series. The crucial difference, as mentioned earlier, is output stage operation—Class AB for Reference Series and Class A for Signature.
As powerful as the RI-100 is, brute force is not the sonic element that stands out—at least not all the time. From day one, what really struck home was the lack of an electronic signature throughout the frequency spectrum. There was no glaze smudging transients, or any dry powdery whiteness over the treble. The RI-100 was supernaturally quiet. I’d describe its character as relaxed but ready. Sure there was impressive transient speed that seamlessly integrated with a rich tonality. But the RI-100 was not euphonic in the classic tube sense of the word, nor was it etched or pushy like less-desirable solid-state. In comparison to some other amps I’m familiar with, its top end would have seemed a tad warm and reserved at first, except for the amount of sheer musicality that poured forth, especially on violin recordings like those featuring Arturo Delmoni [JMR] or Anne-Sophie Mutter [DG]. The RI-100 delicately presented the upper register of the violin as sweetly contained aggression, which is the most concise way I can describe what a violin sounds like at full tilt.
The Vitus conveyed a chesty center of gravity on recordings from the lower mids on down, zeroing in on the substance and weight of brass sections and capturing the full body of a featured saxophone on recordings like Sonny Rollins’ Way Out West. I could pick out with utter clarity the surprising minutiae that humanize a performance—whether it was a creaky piano bench or a rustle of clothing or the flutter of sheet music being turned.
But the RI-100 was also a sleeping giant that could summon a sledgehammer of energy at any instant. As I listened to the bass drum and tympani exchanges of Copland’s Fanfare for the Common Man [Reference Recordings] I felt that I was finally realizing the unrestricted dynamic and visceral potential of this recording. There was more deep-seated rumble, sustain, air, and decay. And this translated into greater insight into the nature of the recording itself.
It also reproduced the delicate world of space and ambience around the music like few amplifiers I’ve experienced. This amp fixed a musical image in a precise position without sacrificing the distinct ambient space that instrument was occupying. It also teased out high-frequency information, harmonics, accurate sibilance, and leading-edge transient cues, and did so with a soft touch. The string sections of Appalachian Spring had buoyancy and a lack of strident edge that on more than one occasion had me recollecting the flawless treble performance of the pure Class A SIA-025.
There are people who will look at an integrated amplifier like the Vitus Audio RI-100 and ask, “What am I going to do with three hundred watts per channel?” My stock reply is, “Eightythree.” As in 83dB, the sensitivity of my long-standing reference compact loudspeakers, the ATC SCM20SL. Every amp that has come through my listening room in recent years has had to deal with this two-way sealed-box compact and its death-defyingly low sensitivity. (Seems to me, when a rating dips this low it should become an “insensitivity” rating.) If you consider that every 3dB decrease in loudspeaker sensitivity requires double the amplifier power to achieve the same sound-pressure level, you’ll realize just how much loudspeaker sensitivity dictates the need for amplifier power.
The ATC will not do bottom octave bass, but driven with the right amplification it is extremely articulate, as it rolls off into the 40Hz range. How does this apply to the RI-100? Marc Cohn’s track “True Companion” [Atlantic] has a bass drum (likely augmented in the studio) that’s softly struck at the end of each verse. I’ve heard this track hundreds of times on a countless number of amplifiers. Systems have a hard time reproducing the extension and detail of this moment, but the RI-100, likely summoning a healthy heaping of its 300 watts, provided more detail and sustain from this cue that these speakers have ever reproduced before.
What constitutes authentic bass reproduction in a system always involves strong personal preferences. The question of control and grip cuts both ways. On the one hand, I expect to hear the resonant sustain and gradual decay of bass information, but if it’s not balanced against a controlled attack the illusion of realism dissolves like so much smoke. By the same token, too much grip can choke off sustain and decay. For example, during Jennifer Warnes’ “Way Down Deep” [Private] I’ve heard the talking drum played by percussionist Paulinho Da Costa run the gamut from flat and tuneless to fat and loose. With the RI-100 I felt I was hearing an ideal balance of transient impact, drum skin flutter, and voicing shifts.
The Reference Series RI-100, on balance, gives away little to its highfalutin’ pure Class A Signature Series siblings. They both present music with astounding presence and energy. Both are fluid and articulate. But the Class A SIA-025 has a riper tonality, and a micro-presence that expresses the smallest dynamic gradients and image clusters (orchestral section layering and choral groups come to mind) in a way the larger amp can’t quite match. By the same token the RI-100 powers through the broader swaths of large-scale symphonies and power rock in a way that makes other amps seem a bit submissive. It’s virtually unrivalled in its breathtakingly tight-fisted low-octave reproduction