Audio Research VS110 power amplifier & SP16L line preamplifier Page 4
A recent exception was a release from Fidelis Records, a company I had not heard of before, of Tchaikovsky's The Seasons, arranged for piano trio by Alexander Gedike and performed by the Tchaikovsky Chamber Music Society. Violinist Atis Bankas, cellist Teymour Sadykov, and pianist Galina Zisk may not be household names, but they're all fine musicians, and the music itself—also new to me—is attractive enough to rival Vivaldi's better-known variation on the seasonal theme. The recording was done in a small church in purist mode, using equipment from Tube Research Labs. Played through the system with the SP16L/VS110 in the chain, the recording had presence and immediacy, with very natural timbres and a good sense of ambience. The subtle interplay among the three instruments was communicated in a way that was easy to follow, and I found myself listening to the music rather than the sound—the hallmark of equipment doing its job right.
Welcome to the real world
As much as I love the Avantgarde Uno, I know that this speaker's high sensitivity and powered subwoofer present an unusual load for an amplifier, so conclusions drawn about the performance of an amplifier using this speaker may have limited generality. To address this issue, I borrowed a pair of conventional dynamic speakers and put the various combinations of amps and preamps through their paces. The speaker I chose was the PSB Stratus Silveri ($1700/pair), a floorstanding three-way that's a more compact version of the Stratus Goldi, rated Class B in "Recommended Components." I chose the Stratus Silveri because I've always admired PSB designer Paul Barton's work but hadn't had the occasion to audition one of his products in my system, and the Stratus Silveri has a small enough footprint that I could place a pair of them in my listening room without having to remove my carefully set-up Avantgarde Unos. The Stratus Silveris were placed in front of the Unos, so that they subtended the same angle.
Putting aside for a moment the discussion of the sonic differences between the preamps and power amps, I was very impressed with the Stratus Silveris. While these speakers lacked that "aliveness" and sense of unrestrained dynamics that the Avantgarde Unos are capable of, the sound was smooth and open, with a wide and deep soundstage, and bass that was surprisingly extended considering the fact that the speakers' positions in the room were not ideal for bass response.
Back to the electronics. As it happened, the first combination that I tried was the SP16L/Eighty-Eight. This worked well in certain ways, the highly musical sound of the Eighty-Eight making the usual positive impression, but the maximum volume attainable with this combination fell short of what I consider acceptable. With some music, I could have the preamp volume set at the top of its range and the sound, while fairly loud, was not as loud as I would sometimes want to have it. This was not primarily due to the limitation in the Eighty-Eight's output, but to the limitation in the maximum output of the SP16L. I was able to get greater maximum volume by driving the Eighty-Eight with the SL-1 Ultimate. I got substantially greater maximum volume still by combining the SP16L with the VS110, or by using the SL-1 Ultimate/VS110 combo. (Those Stratus Silveris can play pretty loud!)
The explanation for these interactions is actually rather straightforward, and has to do with the gain and maximum output level of each preamp, these factors interacting with amplifier gain and speaker sensitivity. As noted above, the SP16L has a maximum 11.5dB of gain, whereas the SL-1 Ultimate's gain is 26dB; their maximum rated outputs are 15V and 50V, respectively. Combine the 11.5dB gain of the SP16L with the 18dB gain of the Audiopax Eighty-Eight to drive the 89dB sensitive Stratus Silveri, and you may have enough volume for the realistic reproduction of chamber trios or solo violins, but not for large-scale orchestral music, big-band jazz, or rock—especially if you have a large listening room (mine is only 14' by 16' by 7.5').
But change just one of the components in this mix to a unit with significantly more gain (14.5dB more from the SL-1 Ultimate, 10dB more from the VS110) and everything is hunky-dory. The SP16L/VS110 combination gave a particularly good account of itself, producing a lively, fast, dynamic sound, with the VS110 maintaining good control over the Stratus Silveris' woofers.
Audio Research has been in the business of producing tube-based audio electronics for more than 30 years. Although their line includes solid-state products—such as the 150M digital multichannel amplifier, premiered at the 2003 Consumer Electronics Show—the SP16L and VS110 are very much in the tradition of AR's classic tube gear, updated with modern advances in design and components. AR products tend to retain their value, a fact related not only to their sound quality but to the company's continuing support for all of their products, past and present. (Owners of the SP-3 preamp, introduced in 1972, can have it factory-updated for $795 to a level that's said to approach AR's current preamps.)
If I had to compare the appeal of the two products, I'd say that the honors are pretty evenly split, the VS110 having potentially broader applicability. This is a truly excellent power amplifier that combines the musicality of tubes with the dynamics and bass extension that characterize the best solid-state, and enough power to drive most speakers to satisfyingly high levels. The SP16L is very good, too, its somewhat laid-back character complementing the VS110's slightly forward quality in a way that's synergistic. In matching the SP16L with other equipment, the factors to watch are amplifier gain (loudness may be limited if the gain is much less than the industry-standard 26dB) and source output voltage (the SP16L's maximum input level of 3.5V is lower than the outputs of some "hot" digital sources).
Individually and, especially, in combination, the Audio Research SP16L and VS110 offer first-rate sound and outstanding value from a company that's one of the leaders in tube audio electronics.