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.
Americans might be forgiven if they haven't heard of Epos. A small, British specialist loudspeaker manufacturer, it was founded in 1983 by its designer, Robin Marshall—an ex-BBC engineer and a onetime consultant to Monitor Audio, according to Roy Hall of Epos's US importer, Music Hall. Their first model, the ES 20, didn't make it to the US, and was apparently a bit too pricey in the UK to make much of a splash there (about £700, $1300 at the current rate of exchange—a mint in a country with the patent on sub-$500/pair (UK prices!) two-ways). In 1986 or thereabouts, the new, smaller ES 14 was introduced, using updated versions of the same drivers in a smaller, ported cabinet. Music Hall only recently began importing the Epos into the US.
I am puzzled. No, really. I know you find it hard to believe that we sacerdotes of the golden-eared persuasion could ever be perplexed, but I have been pondering the imponderables of ports. Ever since the classic work of Richard Small and Neville Thiele in the early '70s showed how the low-frequency response of any box loudspeaker can be modeled as an electrical high-pass filter of some kind, with the relevant equations and data made available to all, there would seem to be very little reason why all loudspeakers with the same extension should not sound alike (or at least very similar) below 100Hz. Yet after reviewing 20 dynamic loudspeakers (and using 24) in the same room over the last seven months, I am led to the conclusion that speakers vary as much in the quality of their mid-to-upper bass as they do in any other region. A few are dry, more are exaggerated in this region; some are detailed and "fast," most are blurred, with the upper bass "slow" (by which I mean that the weight of bass tone seems to lag behind the leading edges of the sound).
Now that Sony has bought CBS's records division, and the infamous Copycode bill seems to be dying in Congress, the way may be clearing at last for the US introduction of the new Digital Audio Tape system. This has sparked renewed speculation in the industry about the impact DAT will have on existing formats, particularly the fledgling CD. Some are convinced DAT will kill CD, because of its ability to record as well as play digital recordings. Others believe DAT won't even gain a foothold in the market, for the same reason quadraphonic sound laid an egg back in the '70s: The public can't handle more than one "standard" format. I feel that both views are wrong, and thatas is usually the case with extreme viewsthe truth lies in between. I believe DAT will catch on in the marketplace, but never in a big way, and certainly not the way CD has. Here's why.
While brushing my teeth this morning, it occurred to me that there are significant similarities between a toothbrush and a tonearm/cartridge. The bristles would be analogous to the cartridge and the brush handle to the tonearm. In either case it is the business end of the device that does all the work. The bristles track the contours of your ivories in search of hazardous waste deposits, while the cartridge tracks the record groove transducing wall modulations into an electrical signal. I think that this is where the old adage came from: "A used cartridge is like a used toothbrushnobody wants one!"
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 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.
It takes more than passing courage to make another assault on building the world's best tube preamplifier. You face stiff competition from well-established firms like Audio Research, Conrad Johnson, and Counterpoint. Such units can't be made inexpensively, and you face the steadily growing problem of tube supply: it is getting harder and harder to get tubes that are stable, have predictable sound and performance characteristics, and are long-lived. And you have to show audiophiles who have been burned before that you will still be around when they need service.
The Model R107 represents the flagship of KEF's Reference Series, and is second only to the Professional Series KM-1 in KEF's product line. Anatomically, the 107 resembles a person. Beneath a decorative "hat," there's a special head assembly akin to the head on the old Model R105. This head assembly contains the brains of the 107, namely a T33 ferrofluid-cooled tweeter and an improved version of the classic B110 midrange driver, featuring a better voice-coil and a new polypropylene cone. The nerve center is also here, in the form of two passive dividing networks and load-impedance equalizing network. Level equalization of the drivers is performed actively within the KUBE, the second brain of the 107—about which you'll hear more shortly.
The Oracle Delphi Mk.II ($1250) is both a turntable and work of art. It is a visually stunning product, retaining a level of styling that, in my view, has never been equalled by any other audio component. It also adds enough sonic improvements to the original Delphi that it ranks close to the VPI HW-19, and is superior, in naturalness of sound quality, to the SOTA Star Sapphire.