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How important is the use of balanced circuit typology in the design of preamplifiers and power amplifiers? Ask the top audio designers (I didn't, but just play along, okay?) and you'll get a wide variety of opinions. Some reject the balanced approach outright, arguing that it represents a needless duplication of circuit components, and that better results can be achieved if the same attention and resources are devoted to perfecting a single-ended circuit. In his provocatively titled article "<A HREF="http://www.stereophile.com//features/335/">Balance: Benefit or Bluff?</A>" (<I>Stereophile</I>, November 1994, p.77), Martin Colloms questioned the advantages of balanced designs, suggesting that while the results may be better in certain respects (<I>eg</I>, noise level), the reproduced sound may suffer in other, perhaps more important ways (<I>eg</I>, rhythm and dynamics).

Victor Khomenko, the "VK" of Balanced Audio Technology's VK-5 preamp and VK-60 amplifier, was born in St. Petersburg (then Leningrad), and grew up two blocks from the Svetlana tube factory. He attended the prestigious Leningrad Polytechnic Institute and received an M.S. in physics and electronics, specializing in electronic emissions. He spent his early working life in the Russian electronics industry, then emigrated to the US in 1979&mdash;with $400, a family, no home, and no job.

Following the introduction of their very expensive, tube/FET hybrid SP11 preamplifier, there were rumors that Audio Research was working on a hybrid tube/transistor preamplifier targeted to cost less than $2000. The rumors were confirmed when ARC showed a black-and-white photo of the SP9 at the 1987 Winter CES. Obviously, like all magazines, we were impatient to receive a review sample, but the first review of the SP9 actually appeared in the summer '87 issue of Peter Moncrieff's <I>IAR Hotline</I>. Peter's review was almost intemperately enthusiastic, comparing the SP9 positively with early samples of the SP11 and suggesting that its sound quality was considerably better than would be expected from its $1695 asking price. Naturally, we were anticipating good things when our review sample arrived in Santa Fe in late July.

The quest for a full-range electrostatic loudspeaker has occupied many engineers' minds for many years. The problems are manifold: large physical size (which can lead to room placement problems and poor dispersion), the difficulty of achieving high sound pressure levels, the need for a potentially sound-degrading step-up transformer, and the unsuitability for production-line manufacture. Even so, the potential rewards are so great that one can understand why loudspeaker designers keep on attempting the apparently impossible. Epoch-making models do appear at infrequent intervals, keeping the flame burning since the appearance of the original Quad in 1955: Acoustat, Sound Lab, and Beveridge in the US, Stax in Japan, Audiostatic in Holland, Quad, of course, in England, and now MartinLogan.

As someone who started out as a classically trained musician but who then stepped sideways into rock, I'm fascinated by the one music I've never played: jazz. It seems to me that the essential difference between a performance of a classical work and a jazz performance is that in the former, the musicians use their technique to breathe life into dead notes on a page, while in <I>good</I> jazz, the performer not only applies a similar level of technical expertise, but also has simultaneously to have all of music theory at the fingertips in order to decide what the next note should be. It is a rare musician---Keith Jarrett, for example---who can excel in both arenas.

<B>Wes Phillips: </B>How did you come to design the <A HREF="http://www.stereophile.com//loudspeakerreviews/477/">WATT</A>&mdash;and the Puppy?

The Bose 901 has created more of a stir in audio circles than any other loudspeaker we can think of, with the possible exception of the original Acoustic Research system. Much of the 901's popularity is attributable to Julian Hirsch's rave report in Stereo Review, and there is no doubt but that Amar Bose's compellingly convincing ads had their effect, too. But these things alone could hardly account for the 901's popularity.