Vacuum Tube Circuit Design: Guitar Amplifier Preamps, Second Edition Paperback – September 8, 2009

I have this book and several other from this author, all of which are very informative. They remind me of the electronic circuits' classes I took in college. If I could change one thing I'd have the figures referenced in the text printed on the adjoining page rather than on the opposite side, as most are done. That way you wouldn't have to continually flip the page to follow the discussion. Otherwise I highly recommend this book for its technical completeness.

Rating: 4.5/5.0This volume takes a unique place in a growing field of books about tube-driven guitar amps at various levels of geek-speak. Kuehnel's text manages to be clear and advanced at the same time. It's the only book I have with a complete and accurate analysis of AC behavior in guitar amp circuits, especially in the grid and coupling circuits, with exact equations that can easily be speadsheeted.Unfortunately, Kuehnel saves his tone stack analysis for his  Bassman book . Instead we get almost 25 pages of input "channel" circuits, and over 40 pages on non-linear impedence factors in circuit components, a tradeoff which seems disputable. The book also comes at a steep price, the page count is deceptive, printed with large page margins, and the softcover binding has a tendency to curl just after the shrinkwrap is removed.In comparison,  Blencowe's preamp book , sturdy with hardbound covers, makes a worthy companion to this one, directed more at modifications, and includes an entire chapter on tone circuits. But Blencowe's 3-band stack analysis is limited to f~1/2piRC estimates, his editing is shabby and generally his books are loaded with errors. Just check pages 3 and 4 of his  power supply book  for typos you can howl about.Kuehnel is far more careful and often succeeds with a *less is more* voice of experience. But if I were to own only one of Kuehnel's books, it would be his  Bassman book , which analyzes the entire amplifier, and applies Cramer's Rule about half a dozen times to derive complete solutions which can be applied to most tube amps in general.Finally I must note both Kuehnel and Blencowe are at the opposite end of the technical axis from  Dave Hunter's popular guidebook . Though his pages are decorated with schematics, Hunter uses language more like a winetaster and offers no circuit analysis at all. After reading all these books, one might conclude that math can describe what our ears hear more precisely than words can.

Many discussions on tube musical instrument amplifier design descend into subjectivity and waffle. Some books, in attempting try to appeal too widely, lose rigor in explanation.Kuehnel's volume manages to avoid becoming mired in theoretical detail yet remains analytically rigorous. The reader is expected to have a firm grasp of basic electronics and electronic components but explanations do not extend into the realm of system-function in frequency domain, laplace and fourier analysis. This contrasts with Kuehnel's seminal volume on the Fender Bassman 5F6-A, which is mathematically much more demanding.The reader here is led quickly through basic triode operation and resistive divider networks. A reasonably comprehensive chapter on guitar pickup characteristics is included, this is extremely welcome as many works on similar subject neglect this topic, which is of fundamental importance. Further chapters cover topics of Miller capacitance, pentode operation, headroom, distortion, noise, cathode degeneration and parallel operation of triodes. The Ampeg B42X pre-amp is analysed, chosen because it does differ somewhat from the more familiar Fender Marshall circuits.In keeping with the desire to use an engineering approach rather than that of a 'guru', Kuehnel includes data on real-world capacitor and resistor performance. He resists the temptation to pontificate on the vintage-component-tone-mojo debate and leaves it to the reader to assess the implications.Tube gear is currently making a bit of a comeback in hi-fi, but it never really went away for guitar amplification.To become a true guru on the topic one can't neglect the value of formal engineering training and recourse to the great texts of the 1950s and earlier by Frederick Terman and Langford-Smith etc. But those texts are general whilst this is specific to subject. Kuehnel doesn't include nearly as much information as contained within Kevin O'Connor's "Ultimate Tone" series but this book is better written, is more textbook like in nature, has fewer errors and in my opinion it is a far better initial investment for those serious about the subject.So, I've just ordered Kuehnel's follow up volume on the power amp to keep the other two volumes that I've already bought company.