A.C. Wente of Bell Telephone Labs was apparently the first person to get the bright idea (in the 1930s) of measuring sound transmission in a small room. A loudspeaker at one point reproducing pure tones of constant power, and a microphone at another point measuring sound-pressure levels, gave him the means to assess the room's impact on sound quality. The measured frequency response was so ragged that I'm positive the venturesome Dr. Wente was duly shocked.
Neither its rather pedestrian name nor Manley Labs' own literature gives much of a clue as to the 175 monoblock's special pedigree. Where are the bands, the fanfare?! After all, the rolling-out of a 6L6based high-power audiophile-grade tube amplifier definitely qualifies in my book as a momentous occasion. Deplorably, such happenings are rare indeed; the 6L6 has been unjustly neglected in high-end circles.
Thanks to Ben Peters, there's an electrostatic lifeline in Holland. Founded about 25 years ago, his company, Audiostatic, struggled through the 1980s, but with distribution by SOTA Industries, it's now on firm footing in the US. In fact, SOTA's Jack Shafton told me that all assembly and some manufacturing are now conducted in the US. My ES-100 samples came from the first US production run.
Lee de Forest filed for a US patent on his "Audion"—the first triode—on October 25, 1906, but never could explain why it worked (footnote 1). It was up to Armstrong and Langmuir, in their pioneering work, to place the hard-vacuum triode on firm scientific ground. When the US entered World War I in April 1917, the Army had to rely on French tubes. Six months later, Western Electric was mass-producing the VT-1 receiving tube and the VT-2 transmitting tube. However, it was only in the decade following World War I, as designers became conversant with the triode amplifier, that many of the crucial elements of tube amplification were nailed down. Technical issues such as coupling two gain stages and selection of optimal coupling impedance were already resolved by the mid-1920s. The triode ruled supreme until the tetrode came along in 1926, followed in 1929 by the pentode from Philips's research laboratories in Holland.
MACH 1 Acoustics? Cute name. Mach 1 is, of course, the speed of sound—the speed at which a loudspeaker's acoustic output is forever constrained to travel. Quite a fitting choice for Marc McCalmont, Marine and jet pilot turned speaker designer. Marc retired to Wilton, NH together with Melissa. (Oops, that should be MLSSA, the well-known acoustic analysis system—not Marc's girlfriend.)
MartinLogan's Gayle Sanders has almost single-handedly raised the electrostatic/dynamic hybrid loudspeaker to a position of prominence in the High End. First, there was the MartinLogan Monolith (reviewed in Vol.8 No.3 and Vol.9 No.3), followed by the much more affordable Sequel (reviewed in Vol.11 No.12, Vol.12 Nos.8, 9, and 12, and Vol.14 No.2). Then came the subject of this review, the Quest, and most recently the diminutive Aerius, reviewed by JA elsewhere in this issue.
In its comparatively few years in the marketplace, the line-level preamplifier appears to have established commercial parity with its full-function big brother. That this was inevitable was clear as far back as the mid-'80s. The advent of the CD and the proliferation of digital sources argued for a modular approach to preamp design. In such an environment, line-level sources (eg, DAT, CD, even analog tape) deserve special attention.
It was back in the mid-'70s that David Berning made a name for himself in the Baltimore-Washington area as an avant-garde designer—someone with a truckload of fresh ideas about tubes. At the time, though Audio Research was starting to crank out pretty decent amplifiers, tube design was pretty much reduced to a rehash of the Williamson circuit and the Dynaco mod of the month.
Let me take you back some 40 years to the mono days of the early 1950s. It's unlikely that the minimonitor genus of loudspeakers, of which this French JMlab is a prime example, would have survived back then. There was the practical problem of available amplifier power. The average amp could squeeze out no more than 10 to 15W into an 8 ohm load—far less power than the typically insensitive minimonitor demands for adequate dynamic headroom. But that in itself would not have sufficed to displace the minimonitor from the marketplace. After all, "high-power" amps (50-watters) could be had at a price.