Eric Barbour has been an applications engineer with Svetlana Electron Devices Inc., Portola Valley, Calif., since July 1996. His work involves testing and characterizing new vacuum-tube types and constructing and testing amplifier circuitry for Svetlana audio and RF tubes. Earlier, he was a senior technician and then an engineer with the U.S. Department of Energy, Intelligent Electronics Co., and Dionex Corp.
A staff editor of Vacuum Tube Valley magazine, Sunnyvale, Calif., since its founding in 1995, he also contributes to Glass Audio magazine, Peterborough, N.H.
Well-written articles on the subjective and objective characteristics of tube audio electronics include: “Why tubes sound so good,” by Doug Fearn, Pro Audio Review, January/February 1996, Vol. 2, no. 1, p. 15; “The grounded ear” Peter Sutheim’s column in The Audio Amateur, Issue 3, 1980, p. 34; and “Tubes versus transistors— Is there an audible difference?” by Russell O. Hamm in Journal Of the Audio Engineering Society, May 1973, Vol. 21, no. 4, p. 267 (reprinted in Glass Audio, Issue 4, 1992, p. 16 on).
An unusual approach to testing for distortion products in power amplifiers is taken in “Spectral contamination measurement,” by Deane Jensen and Gary Sokolich, presented at the 85th AES Convention, 3-6 November 1988 (Audio Engineering Society, New York City, 1988). Spectral distortion products of transistor amplifiers are compared, along with those from a McIntosh MC-30 tube amplifier, whose spectral plot is quite different from those of solid-state amplifiers.
In professional recording, tube equipment is a small but growing field. Recent articles about it include: “Tube processors—The outboard renaissance,” by Loren Alldrin, MIX magazine, May 1997, Vol. 21, no. 5, p. 108; “A reader’s guide to vintage gear,” by Fletcher, MIX, November 1996, p. 84; “Retro-Active,” by Michael Molenda, Electronic Musician, June 1995, p. 36; “The retro movement,” by Sue Sillitoe, Audio Media, November 1994, p. 48; and “The vacuum tube rides again,” by Walter Sear, MIX, May 1994, p. 24.
Textbooks on professional audio equipment design using tubes are a quite recent phenomenon. The most useful include Principles of Power and The Ultimate Tone, by Kevin O’Connor (Power Press Publishing Co., London, Ont., Canada, 1996); Vacuum Tube Guitar And Bass Amplifier Theory, by Tino Zottola (self-published, 1997); and Dan Torres’ Inside Tube Amps (Sparpco Inc., San Mateo, Calif., 1996). An unusual reference book, with hundreds of schematic diagrams for tube-based music equipment is Aspen Pittman’s The Tube Amp Book, edition 5 (Groove Tubes Inc., Sylmar, Calif., 1995).
Suitable for novices is Beginner’s Guide To Tube Audio Design, by Bruce Rozenblit (Audio Amateur Press, Peterborough, N.H., 1997). All the books are available from Antique Electronic Supply, 6221 S. Maple Ave., Tempe, AZ 85283.
A taste of the fascinating and obscure world of “boutique” guitar amplifiers is afforded by Art Thompson’s “20 mule duel: we wrangle a herd of new boutique amps,” in Guitar Player, February 1997, Vol. 31, no. 2, p.118.
Plenty of publications intensively cover vacuum-tube audio electronic design. Their emphasis is usually on hi-fi audio, although material about guitar amps and professional studio electronics appears regularly. English-language publications include Glass Audio (Box 176, Peterborough, NH 03458) and Vacuum Tube Valley (1095 E. Duane Ave., Suite 106, Sunnyvale CA 94086).
Magazines that concentrate on high-end audio design include Sound Practices (Box 180562, Austin, TX 78718), Ultra-High Fidelity (Box 158, Cheshunt, Herts., EN7 6UH, UK), and Valve (Box 2786, Poulsbo, WA 98370).
Non-English tube-audio publications include:
The Italian Audion (Piazza Madonna Aldobrandini 7, 50123 Firenze) and Costruire Hi-Fi (Via Toti 9, 20010 Bareggio, Italy).
The Japanese MJ Audio Technology (Seibundo Shinkosha Publishing Co., 13-7, Yayoicho 1-chome, Nakano-Ku, Tokyo 164, Japan).
The French Musique et Technique (Bureau de Depot 1050, Brussels 5, Belgium).
The German Hi-Fi Scene (Dufourstrasse 165, CH-8008 Zurich, Switzerland).