European Triode Festival: It moves around every few years, recently in Denmark. Absolute die-hard tube fans here. I try not to miss it!
The Art of Electronics, Paul Horowitz and Winfield Hill: The classic. One really excellent pedagogical trick is the pages of “Bad Circuits.” Spotting the errors is VERY educational. Anyway, this book is great to learn from, clearly written, and time-tested. The mix between theory and practice is cannily chosen, and there’s a nice emphasis on estimation techniques. I don’t know anyone who does electronics who doesn’t own a copy, and there’s a reason that this is the most popular introductory text at the university level. You will need to know basic algebra, trigonometry, and calculus. The 3rd Edition is a very worthwhile upgrade.
Troubleshooting Analog Circuits, Bob Pease: This indispensable book, from one of the gurus of analog circuit design, falls squarely in the “practical” camp. It assumes you know basic electronics, but will then arm you with a lot of great tools to make real bits of silicon and copper do your bidding.
The Radio Amateur’s Handbook, ARRL. My copy is antique (1966 edition), falling apart, solder splashes and notes on every page. That’s a pretty strong endorsement.
Testing Loudspeakers, Joe d’Appolito: This is an essential book for loudspeaker constructors. Modern test tools (FFT analysis, MLS, and the like) have the capability of producing lots of profound-appearing garbage. And the resulting speaker “designs” often show it. To use these powerful tools effectively, one must understand them and their quirks and limitations. d’Appolito does a fine job of explaining the necessary mysteries of binning, windows, anechoic versus ground-plane versus near-field, and so on and so on. For less than the price of a sound card, this book can help you get useful, accurate, and reliable measurements.
Tubes and Tube Amps
Valve Amplifiers (4th Edition), Morgan Jones: A modern look at the engineering of tube (“valve”) amplifiers, Jones starts with the basics, then step-by-step takes the reader through each of the building blocks of the electronics chain. A bit of the opposite of Crowhurst in that Jones doesn’t try to analyze every trick circuit out there, but goes into detail about the most useful ones. Also noteworthy is his analysis of distortion by tube type (naming names) and a detailed look at the effects of various geometries and methods in tube manufacture on the tube’s performance. The particular thing that appealed to me was his free use of modern technology and techniques to extract the most out of an antique art-form. And unlike the previous books in the genre, Jones presents several construction projects to illustrate the theoretical expositions earlier in the book. Anyone even vaguely serious about tubes in audio should own this; my copy is as ragged as my favorite Julia Child cookbook, the highest testimonial.
Understanding Hifi Circuits, Norman Crowhurst: In this tube-oriented book, Crowhurst surveys all the bits and pieces that make up a complete circuit design. If you want to know why the cathode follower is not often used as an output stage, why too many rolloffs turn an amp into an oscillator, and the merits and demerits of passive EQ for RIAA amps (just to name a few examples), you’ll find it here. Crowhurst was an excellent teacher and writes with great clarity. There’s not an enormous amount of in-depth discussion here, but the coverage is very broad.
High Fidelity Circuit Design, Norman Crowhurst and George Cooper: A bit richer and more advanced than the previous text, the really outstanding thing here is a readable treatment of the use of the complex plane to determine stability of feedback systems. Like the previous text, well-written and highly useful.
Radiotron Designers Handbook, 4th edition, Francis Langford-Smith: This is veritably the Old Testament for the vacuum tube enthusiast. The language is dense and terse, the coverage comprehensive. One of the must-haves.
AudioXpress: The descendant of Audio Amateur, Speaker Builder, and Glass Audio. Don’t take everything you read in there seriously, but there’s enough from really skilled and talented engineers to make it worth many times its price.
Linear Audio: The editor, Jan Didden, has decided that he would collect articles from technical experts and focus more on conceptual and analytical articles than construction projects by enthusiastic (but not always competent) amateur designers. The result is a bookzine that’s at a professional journal level. Jan decided to wind things up after Volume 13, but the collection is still available at the link, and is certainly a classic in the world of audio. This is a must-have.
diyAudio: Far and away the largest site for discussion of audio design and construction. Relatively tight moderation means a higher signal to noise than most forums.
Pete Millett: Pete has a fine assortment of projects, an invaluable library, and some first-rate technical writing. His designs are very clever and engineered flawlessly.
Linear Audio: This site is the creation of Jan Didden, from whom I learned everything I know about regulators in audio. Jan has been exploring feedforward techniques in solid state amps recently, and his stuff is very educational.
Pass Labs: This is the eclectic and impressive site of Nelson Pass, a truly original thinker. Nelson has probably done more to advance the cause of amateur audio than anyone else in the past couple decades.
Tube Cad: It is said that tube topologies are very limited because there are no “p” tubes, just “n.” John Broskie is living proof that this is not necessarily the case. His articles are Mr. Toad’s Wild Ride through design. I don’t use his software (I still do loadlines with ruler and pencil), but it looks excellent. I have built some of his kits and used his boards and can vouch for their quality. I can also say that John is a real mensch.
Duncan Amps: A treasure trove of info on tubes. The software section is incredible. PSUD II may be found here, and trust me, you need it.
Frank’s Tube Data Sheets: This is a staggering collection of tube data sheets. Frank Philipse has rendered an invaluable service to tube experimenters. Probably my most-visited site overall.
tubelab.com: George is not only willing to go where lesser mortals fear to tread, he’s there to kick ass and take names. This is a pile of creative and fun engineering. He’s the Ted Nugent of tube amplifier designers.
John’s Valve Page: John Harper is an engineer who has put together some superb material. His review of vacuum tube operation is a very clear explanation that is a convenient and valuable reference any time I need a basic formula. The other stuff on his site is quite first-rate also.
Kevin Kennedy: Kevin is a solid and experienced engineer whose designs are straightforward, well-documented, and refreshingly free of voodoo. Lots of interesting information there.
PSUD2: A power supply design program, meant for simulating unregulated supplies. Remarkably accurate and extremely useful- will transformer X give me the voltage I need? Will a pi filter get the ripple down to what I need? Will the supply ring when hit with current steps? The user interface is a bit idiosyncratic, so expect to spend a little time fooling around before you get the results you’re looking for. Available free at the Duncan Amps website.