Convergent Audio Technology SL-1 preamplifier Russ Novak 1995
My reference system consists of Mirage M1si speakers driven by a Krell KSA-250 amplifier, TARA Labs' superb new RSC Master Generation 2 speaker cables and interconnects, a Museatex CD transport with re-clocking circuit, a Monarchy DAC, a Clear Image Audio T-4 Power Line Isolator, and a Bright Star Big Rock/Little Rock isolation system (sand bases and weights). The system was run balanced between the amp and preamp, but had to be switched to single-ended operation for the preamp comparisons following the general listening. I also chose single-ended connection for the Monarchy DAC. Perhaps because I didn't have an extra set of balanced interconnects of RSC quality, I couldn't achieve the beautiful sound I obtained from the Monarchy using single-ended Kimber Kable KCAG.
After a casual listen to the CAT, I called the guy who loaned it to me and told him it was no contest in the old "palpable presence" category. The CAT, I thought, had a clear advantage in dimensionality and sweetness. The sense of depth extended from the speakers to forever. Notes emerged from a very black background. Nothing was disturbing. Everything was sweet.
The next night I sat down with both preamps, a pen and paper, and my selection of test CDs, and became unsettled with the CAT. After four selections—about 40 minutes of listening—I grew tired of the formatted sound. My early notes reflected enchantment: liquidity, space between instruments, lack of glare, a large rectangular soundstage beginning well in back of the speakers, romance. Such was the case with Orquesta Nova's "Milonga Del Angél" (Salon New York, Chesky JD86)—a superbly recorded work, and very romantic in its own right.
But by the time I got to my third selection—Tobias Picker's "Old and Lost Rivers," from The Encantadas (Virgin Classics 59007)—I was noting that everything seemed very distant. The strings, which have a lot of information in the upper octaves, and upon which this recording hangs its emotional hat, were much subdued. In a composition with little dynamic range, what dynamics there had been were now virtually absent.
Dynamics, and consequently the perceived pace and tempo of the music, suffered with the CAT in comparison to the SFL-2. Chico Hamilton's "Passin' Thru," from Man from Two Worlds (GRP GRD-127), is typical of multi-miked jazz recordings. "Lazy," commented a friend. The bass, guitar, and drums simply didn't propel the music the way they were meant to be propelled. Through the CAT, the group seemed to be playing in a sedate parlor setting; through the SFL-2, the music was immediate and had more "jump factor"—as a jazz performance should. Furthermore, the CAT placed the tenor sax and trombone well behind the speakers—about 4'. This wasn't unpleasant, just inaccurate for a multi-miked recording in which the instruments should appear much more forward on the stage.
In comparison to the SFL-2, the CAT was rolled off on the top and bottom. Tape hiss, audible with other preamps on Frank Sinatra's Only the Lonely (Capitol C21Y 48471) and on Max Bruch's Kol Nidrei with János Starker (Mercury Living Presence 432 001-2), wasn't there with the CAT. Not that I want to hear tape hiss, but if it's there, it's there, and it indicates what the preamp is doing to the sound. In every recording, the SFL-2 had the more extended, transparent sound.
Both preamps were pleasing in the midbass, but the Sonic Frontiers had much more extension. The "thumping around" in the bass region during the opening bars of Sinatra's "Blues in the Night" was deeper, more dynamic, more dimensional, and much more transparent with the Sonic Frontiers. The CAT was "nice," but didn't pass on the information. My observation of the difference in bass extension and dynamics was confirmed by playing Bach's Goldberg Variations transcribed for organ (Jean Guillou, Dorian DOR-90110).
Finally, Sinatra's voice through the CAT was a bit syrupy, and surrounded by too much blackness. "Blues in the Night" was the last piece I listened to, by which time I'd grown too used to the CAT's sonic signature. It still can't be beat on a first impression in the "palpable presence" category, which for many is the most important thing. But the CAT is not as accurate as the SFL-2—or, ultimately, as musical. I've listened to the Sonic Frontiers for hundreds of hours without experiencing auditory fatigue, but I grew impatient with the CAT's sound in one evening. I think it would be a savior for bright, etched, or analytical systems, but the SFL-2 simply outdistanced it on top and bottom extension, dynamics, and transparency.—Russ Novak