Dick Olsher, J. Gordon Holt, John Atkinson

Stax Kogyo, a small audio company by Japanese standards, has been for the past 15 years steadfastly refining and redefining the electrostatic headphone. The SR-Lambda Pro is their current flagship model, and at a 1984 US list price of $780 it also represents a very substantial investment in headphone technology.

I do quite a bit of headphone listening during the day, making use of their convenience to shut out the office hubbub while I get down to serious copy editing. The system I use is modest—a pair of no-longer-available Sennheiser HD420SLs driven by an Advent 300 receiver I bought for $75, with CD source provided by a Denon DCD-1500 II—but I get quite a bit of musical satisfaction from it.

Editor's Note: One-bit DAC chips in the 21st century, where the analog output signal is reconstructed from a very high-rate stream of pulses, are ubiquitous. But a quarter-century ago, those chips were only just beginning to stream from the chip foundries. In this feature, we aggregate Stereophile's 1989 coverage of the then-new technology, starting with Peter van Willenswaard on the basics.—John Atkinson.

1989 may well become the year of the D/A converter (DAC). CD-player manufacturers have, almost without exception, launched research projects focusing on this problem area of digital audio; many of these projects are already a year old. This is, however, by no means the only imperfection keeping us away from the high-quality sound we have come to suspect is possible with digital audio media, and maybe not even the most important.

When Pass Labs is mentioned, it's natural to think of its founder, iconic engineer Nelson Pass. But Nelson heads a team of engineers at the California company: Their XP-30 preamplifier, which I enthusiastically reviewed in April 2013, was designed by Wayne Colburn; and the subject of this review, the HPA-1 headphone amplifier, is the first Pass Labs product designed by Jam Somasundram, former director of engineering for Cary Audio. Somasundram joined Pass Labs in July 2013; he spent a year working on the HPA-1, which was shown at the 2015 Consumer Electronics Show, in Las Vegas, but not formally launched until the 2016 CES, at a hefty $3500.

My beat at T.H.E. Show 2016 was the ground floor. En route to the audio exhibits, I was stopped dead in my tracks by this beautiful black Bugatti. No information on this particular car was available, but I assumed it was part of the display of tasty automobiles in the Hotel Irvine's lobby and outdoors pavilion, put on by Reus Car Audio Design, Whitledge Design, Wyred 4 Sound, Magnum Automotive Design, and The Source Audio Video Design Group. Pride of place in the car exhibit was Sony's Hi-Res Audio demo vehicle, which had been shown off two days earlier at the Capitol Studios event in Hollywood.

Driving the Model Sevens at the 2014 CES were Vandersteen's then-new M7-HPA monoblocks, which provide a high-pass–filtered output (above 100Hz) to the upper-frequency drive-units of the Model Seven. At the time, I made a note to myself that I would like one day to try these amplifiers with the Sevens in my own room. That opportunity came later rather than sooner, after Vandersteen had updated the Model Seven to Mk.II status.

Sad, sad news - and he did the best SuperBowl Show evah!

https://www.youtube.com/watch?v=7NN3gsSf-Ys

One of my music heroes.