We thought Audo Research's previous-model SP-2C (footnote 1) was excellent, but this is even better—the closest thing available, in fact, to the ideal straight wire with gain. Our sample had a minor glitch—there was a slight "plop" if you rotated the tone controls rapidly—but we could find nothing else about it to criticize. Currently, by far the best preamplifier than money can buy. And would you believe it uses tubes (at reduced heater voltage, for extended life and cooler operation)!
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 IAR Hotline. 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 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.
Not only does the venerable vacuum tube refuse to lie down and die, as everyone predicted when audio went solid-state; it continues to deliver better performance than anyone had imagined it could. Only a few years ago, we could characterize "the tube sound" as being sweet but soft at the high end, rich but loose in the midbass, deficient in deep bass, and bright and forward, usually with excellent reproduction of depth. Since then, we've seen the introduction of what might almost be called a new generation of tube amplifiers, which rival solid-state units in those areas where tubes used to have weaknesses, but have given up little of the tube's sonic strengths.
Warning to Purists: Despite certain qualities about the ESL-63 speakers which you will probably like, Quad equipment is not designed primarily for audiophiles, but for serious-music (call that "classical") listeners who play records more for musical enjoyment than for the sound. Quad's loudspeakers do not reproduce very deep bass and will not play at aurally traumatizing volume levels, and Quad's preamplifier is compromised through the addition of tone controls and filters, all for the purpose of making old, mediocre, and/or worn recordings sound as listenable as possible.
The Sound-Lab electrostatic loudspeakers are legendary. Many serious audiophiles have heard of them, and rumors of their existence abound in audio circles. But, like gnomes, UFOs, and poltergeists, Sound-Lab loudspeakers are sufficiently hard to find that it is sometimes difficult to prove to skeptics that they exist at all. Well, I can now report that they do. As proof of this contention, I can point to the two which are actually occupying solid, tangible space in my listening room at this very moment. I have even taken a photo of them, which will be published along with this report if they leave any sort of an image on the film emulsion. (Many such apparitions do not!)
For those of us who have succumbed to the enticements of surround-sound for music, Audio Research's SDP1 is both vindication and cause for rejoicing: vindication because surround-sound's acceptance by such an ultraconservative, uncompromising company as ARC will give it a respectability in the high-end community that it never enjoyed before, and cause for rejoicing because someone has finally done music surround right.
The D-250 is the flagship of Audio Research's power amplifier range and, at 250 watts per channel, is the most powerful all-tube stereo amplifier currently available in the US. Under the circumstances, then, it is not surprising that it should also be one of the heaviest and largest.
This is something we don't see too often: an entirely new approach to power amplifier design. As Quad points out in its literature for the 405, class-A operation of transistors provides the lowest distortion, but drastically limits the amount of power an output transistor can deliver without overheating. (Most transistor amps use class-AB output operation, in which each of a pair of power transistors handles part of each signal cycle and shuts down during the other part. Imperfect synchronism between the two halves causes the familiar "crossover distortion," which accounts for most solid-state sound. In class-A operation, each output transistor draws current though the entirety of each signal cycle, eliminating the crossover transition but doubling the amount of time current is drawn, and thus tending to cause the transistor to heat up more.)