I grant you, the Q&A format of the original Cyclopedia
is silly and the subjects don't often follow a logical sequence, but overall I still think it's an important book. I own a number of books from the "classic" era of audio and Tremaine is by far the most wide-ranging. You can find more rigorous treatments of circuit theory elsewhere, but nobody gave a broader survey of the state of the audio art at the time.
As for the 3rd edition of the Ballou book... Yes, I own it. It was a very expensive impulse purchase. I wouldn't buy it again at the same price.
It
does contain some superb material (my personal favorites are Steve Dove's chapter on console design, now updated, Bill Whitlock's chapters on audio transformers and preamps, Dale Manquen's opus on magnetic recording), but it also has a few things that piss me off. The book has several silly typos that I consider unacceptable in an expensive professional text. Also, fairly large sections (e.g., much of the chapter on equalizers) are lifted nearly verbatim from Tremaine without credit given. Matter of fact, Tremaine is only mentioned in passing in the preface, and they spell his name wrong!
The book is worth having for the "good" chapters, but my advice is to wait a while until used copies become available... or buy it out of your employer's budget, not your own. :wink: