Linear Audio’s mission is the dissemination of technical audio information, to benefit professional designers and advanced amateurs alike. Since the inaugural Volume 0 the publisher has successfully added well-known and very knowledgeable authors to its roster. The website at www.linearaudio.net has a full list of authors and their biographies, in recognition to their contributions to the publication. The list reads like Who is Who in tech audio: Nelson Pass, Bob Cordell, Scott Wurcer, Douglas Self, Barrie Gilbert, Erno Borbely, Gary Galo, Malcolm Hawksford, Ian Hegglun, Morgan Jones, Siegfried Linkwitz and many others.
Each Linear Audio issue has a mix of article subjects, not only electronic design and engineering articles but also articles on speaker design, perception and controlled testing, test equipment design, digital signal processing and others that have a technical link to audio. New or updated books on audio technology as well as unique hardware or software products are also reviewed by knowledgeable reviewers.
Linear Audio Volume 8 is the latest issue, published 1 September 2014. Its contents is a smorgasbord of creative, innovative and thought-provoking articles. An overview:
Stereophile’s Editor in Chief John Atkinson explains how he makes sure equipment reviews are useful for his readers, and why he includes measurements with listening reports. Then there are several circuit design articles, ranging from a 100W single-ended tube amplifier with less than -80dB distortion at full power (honestly!) by Frank Blöhbaum; the second installment of an article series about error correction methods for power amplifiers and its application, pitfalls and advantages, by Giovanni Stochino; the final part of a design for a fully balanced phono preamp using JFETs, tubes, MOSFETs and integrated circuits (aptly called The Equal Opportunity phono preamp) by Stuart Yaniger; all you always wanted to know about designing and sizing power supplies for your equipment by Rudolf Moers; a simple way to estimate – and compare! – the noise contributions of phono preamps from Marcel van de Gevel; and Ian Hegglun’s very revolutionary out-of-the-box power amp relying on MOSFET cube law transfer characteristics to come up with a class A design with only ¼ of the quiescent current of ‘regular’ class A (and each copy of Volume 8 comes with a free PCB for this design, courtesy Ian Hegglun and Eurocircuits).
On the digital front there is an article by Hans Polak explaining the implications of the Nyquist-Shannon Theorem for digital audio processing.
Tube authority Morgan Jones reviewed the uTracer V3.10, a PC-controlled curve tracer for tubes, while David Moran reviews Floyd Toole’s Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms.
As usual, Volume 8 is concluded by a column from Stan Curtis, this time about whether size does matter in low frequency drivers.
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