Avantgarde Acoustic Uno Series Two loudspeaker Page 5
However, if I start to get analytic about it (there I go again...), I have to admit that the bass was somewhat on the mushy side, and there was some compression of dynamics at the high levels the Uno is capable of. The Balanced Audio Technology VK-60 (60Wpc, a modern bridged-SET design) had more extended, tighter bass and greater dynamic headroom, and its midrange was almost as good as the Cary's (footnote 3).
In both cases, the preamplifier was the $6000 Convergent Audio Technology (CAT) SL-1 Ultimate, with a digital front end costing $3-$5k, and power amps in the $4-$5k range—not quite price-no-object, but still pretty expensive. (The $1895 Cary SLP-50B preamp proved a credible alternative to the CAT: very sweet-sounding and musical, if less transparent and extended at the frequency extremes.)
To check out what the Uno might sound like with more moderately priced components, I set up a system consisting of a Rotel RCD-991 CD player ($1395) and YBA Intégré DT integrated amplifier ($2345, 50Wpc). Cables were still the pricey Nordost Quattro Fil/SPM, but I wanted to keep this part of the system as a constant. The results were more "mainstream" in tonal balance (less warmth, brighter) than the tube-based systems, but were very satisfying overall.
In general, I'd say that if you have a predilection for a certain type of amplifier design (solid-state or tube, single-ended or push-pull, Class Whatever), there's a good chance that it can be mated with the Uno. When you're shopping for an amplifier to match the speaker, keep in mind that the one with the lowest power in a given amplifier line is likely to be more than adequate, and usually sounds better than its higher-powered siblings.
Two technical aspects of the compatibility between the Uno and associated equipment that have to be considered carefully are preamplifier output level and amplifier gain. The Uno's high sensitivity makes the amount of residual noise in associated components critical, and some preamp/amp combinations that work well with less sensitive speakers are problematic with the Uno. The CAT preamp/Cary amp combination had an acceptably low noise level with the Uno, but the CAT driving a Bryston 9B-ST, an amplifier with extremely low inherent noise but high gain, resulted in annoyingly audible tube noise coming through the speakers. (The same preamp and amp with Dunlavy SC-IV/A or Vienna Acoustics Mahler speakers was dead quiet.) I'm told by Bryston's James Tanner that lowering their amplifier's gain is a simple internal modification involving the addition of some resistors; I assume this to be the case for other amplifiers as well.
The illusion of "liveness" in reproduced sound is a delicate perceptual phenomenon dependent on the source material, equipment, room, and time of day, as well as the listener's mood and expectations. I have experienced this illusion in the past with some speakers in my system, but only rarely and in a fleeting manner. With the Avantgarde Uno, it was a frequent occurrence, and persisted for longer periods before something about the sound acted as a reminder that I was listening to a recording.
At times, the sense that these singers and musicians had somehow appeared in my listening room and were performing for me was quite spooky. Was this merely coincidence, or fortuitous system synergy? I don't think so. The effect was too consistent, and held up with changes in associated equipment. The Uno created the illusion of "liveness" better than any other speaker I've had in my listening room. In fact, I can think of few speakers I've heard anywhere at any price that sounded as convincingly "live" as the Uno. At just under $11k in the standard finish, the Uno is not inexpensive, but its sonic rivals cost very much more, and the Uno's high sensitivity means that you don't need an expensive high-powered amplifier to drive it.
In selecting a speaker, especially at the highest levels of performance, individual likes and dislikes play important roles. Some people may be bothered by the Uno's residual horn coloration, even though its magnitude is small. I wouldn't suggest buying a speaker based only on the recommendation of a reviewer—even if the reviewer is me! What I do suggest is that anyone who can afford speakers in this price range, and even those who can also afford speakers of the price-no-object variety, give the Uno a serious listen. It is simply that good.
Footnote 3: The combination of the CAT preamp, BAT power amp, and the Unos resulted in a fairly high level of AC buzz coming though the speakers that I was unable to eliminate through changes in grounding, etc. The CAT preamp is unbalanced, so connecting it to the BAT power amp requires RCA-to-XLR adapters. In theory, this arrangement is not ideal, but it produced very little AC buzz when using Dunlavy SC-IV/As, so the difference might have to do with the Avantgarde's higher sensitivity, or may represent one of those mysterious system interactions. Balanced Audio Technology's VP of marketing Steve Bednarski and sales manager Geoff Poor both own Avantgarde speakers, and Jim Smith uses BAT equipment in some of his demos, so I'm pretty sure the Uno can work well with all-BAT electronics.