This book really is a tool box — a one-stop resource for everything you need to design and build a tube-based audio power amplifier. This self-published book has the same content quality as a book from the larger publishing houses. It has a hard cover and has many color print pages (unheard of at this price). Clearly a work of love!When I showed this book to one of my audio friends, he commented: “This is not a tube amplifier book!” And he would be right—because it is so much more. Imagine you are looking for information on how to design and build an audio tube amplifier. You get one of the many available books, but you’re not done yet. During the course of your design, you also need to check, for example, how that input low-pass filter must be dimensioned. You know that grid leak resistors are important for low noise, so you need to investigate the different resistor types and their properties. Same (or even more important) for capacitor types. If you haven’t decided yet on which tubes you want to use, it would be nice to have an overview of types that are usable for audio in their different roles, and how to bias them and construct the load lines. With that out of the way, the design process can start in earnest—no, wait, you also need an output transformer! Which type, for which application and power, or maybe wind one yourself? Then, to cap it all off, there’s the not insignificant issue of dependable and low noise power supplies.
Well, you get the point.
Structure
At 428 pages, and with treating so many different subjects in some detail, the book doesn’t waste page space. Each page is filled with to-the-point information, circuit diagrams, graphs, equations, and example calculations. But have no fear—the math never goes beyond elementary high school algebra. Figure 1 shows a representative image from Chapter 1, Elementary Acoustics. Figure 2 shows a representative image of Chapter 4, Vacuum Tube Electronic Circuits.
The other chapters are titled Passive Electronic Components (Chapter 2), Basics of Vacuum Tubes (Chapter 3), Transformers (Chapter 5), Power Supplies (Chapter 6) and Power Amplifier Design Practice (Chapter 7). The book ends with a final chapter on measurement and testing (Chapter 8).
Chapter 5 in itself would be worth the price of the book. It is a very complete treatment of everything of importance for output transformers. Starting with explanations on transformer operation and parameters, it includes many tables on the properties of various core materials (e.g., GOSS and NOSS and configurations). Selection tables are also offered on wire sizes and current capabilities for several wire and insulation types. With that out of the way, it is on to transformer specifications, equivalent circuits, and calculation of transformers for specific output stage examples. Again, complete, to the point, and extremely useful.
I don’t want to repeat myself, but again, Chapter 6 on power supplies is simply complete, going from mains rectification and smoothing, to a section on calculating choke induction for specific use cases (Figure 3), inrush current limiting, DC regulators for DC heater supplies, and how to wire up AC heaters for minimum hum (Figure 4). High-voltage delay circuits are also offered. And all subjects are complete—the section on DC heater supplies also includes information on heatsinking of regulators with selection tables.
After finalizing these steps, you will have a complete amplifier schematic with component values. You do the same exercise for the power supply, developing the circuit with component values. Next, it is time to select the parts for the amplifier and layout the chassis and position of the mechanical components. Then, it is on to mounting the components and parts, wiring up the amplifier, and last to measurements and testing.
As mentioned, Chapter 8 offers a detailed guide to measuring your amplifier, from frequency response to distortion, noise and input impedance. There is a paragraph on how to interpret the square wave response, using it as a diagnostic tool. It even shows you how to measure the temperature of a transformer or resistor if you are worried about the high temperature of parts.
There are a lot of steps in Chapter 7 and Chapter 8, and some are recurring, but it is the most effective design process I know and will almost guarantee a fine working amplifier you can be proud of as a result. As they say, everything worth doing is worth doing well, and that certainly goes for audio electronics design.
Wrap-Up
This book is a veritable tool box that contains all the “tools” you need to design and build a tube-based audio amplifier. You would need at least a foot of bookshelf space for traditional audio electronics books to collect the same information as is presented in this single volume. Zoran Dukic clearly writes from a position of expertise and experience, not just theory, although theory is not neglected. If you are serious about tube amplifier design, there’s one book you absolutely need—this one. Highly recommended. aX
Author’s Note: Readers interested in purchasing this book should contact the author at this email.
High End Tube Amplifiers Designer Tool Box
Zoran M. Dukic, self-published, 2023
Hardcover, 428 pages
ISBN 978-86-6233-517-3
Approximately $50.
About the Book’s AuthorZoran M. Dukic was born in 1953 in Kraljevo, Serbia. He had an early interest in physics and became the Yugoslav high school winner in the national physics competition in 1971. In 1978 he graduated from Nis University in Serbia. He started his professional career in the electron tube factory at Elektronska Industrije Nis, eventually working his way up to the position of General Manager, and Vice President of the holding company. Throughout his active career he continued his interest in the development of vacuum tube production, production re-engineering and manufacturing of a modern assortment of tubes with special application in audio devices — high-end amplifiers and guitar amplifiers. The unfortunate events of the 1990s with hostilities in the area and the subsequent unsuccessful privatization during the transition process interrupted the comeback and repositioning of the Ei Electron Tubes factory on the world market. In 2023, after retirement and at the insistence of an audiophile friend, Zoran wrote the book High End Tube Amplifiers Designer Tool Box.
This article was originally published in audioXpress, March 2025
