Fundamental Amplifier Techniques with Electron Tubes

Le point de vue de Francis Ibre :

Plus d’un siècle après son avènement, il aura fallu plus de 800 pages à Rudolf Moers pour compiler l’ensemble des savoirs sur le tube électronique et ses applications dans les amplificateurs audio.
Ces connaissances indispensables pour la conception et les calculs relatifs aux circuits à tubes étaient disséminées jusqu’ici dans des livres anciens, parfois introuvables. Théorie, circuits de base et éléments de mathématiques associés sont désormais réunis en un volume. Cette publication comblera les nombreux amateurs désireux de concevoir et réaliser leur propre amplificateur, mais gênés par l’absence de littérature récente.

Depuis la diode à vide, utilisée en redressement simple ou double alternance, en passant par la triode amplificatrice de tension, ou de puissance, en simple étage ou push-pull classe A ou AB, jusqu’à la tétrode et la pentode avec le montage ultra-linéaire, tous les circuits sont présentés, avec les grandeurs physiques mises en jeu, puis analysés par le calcul dans les moindres détails.

Le lecteur apprendra non seulement à choisir un point de fonctionnement, à tracer une droite de charge, à calculer le gain d’un circuit et son impédance de sortie, mais aussi à calculer la résistance nécessaire dans le circuit d’anode d’une diode redresseuse.

Les sujets abordés dans cet ouvrage exhaustif couvrent l’adaptation de l’impédance de charge, le rendement, l’amortissement du haut-parleur, ainsi que le transformateur de sortie et ses limites, les composants passifs et les distorsions, les bruits divers, les effets de la contre-réaction, avec à chaque fois les outils de calcul nécessaires.

Chaque chapitre donne des exemples concrets de conception de circuit, et des comparaisons entre théorie et pratique, à partir des mesures obtenues sur les circuits réels.

Un livre indispensable dans la bibliothèque de tout amateur.

F. Ibre - février 2011 

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For years, author Rudolf Moers searched for a textbook about electron tube amplifiers in order to learn how to design amplifiers using electron tubes, given that one has a reasonable knowledge of analog electronics. Since he never found such a book, he has written one himself in a style and content such as he would like to buy. To achieve this, he studied many radio books and did many measurements. This was followed by the organization of all the information, making many drawings and calculations and a lot of writing. By all this effort, a lot of knowledge about electron tube electronics, which was under the threat of being lost, will be retained.

There are two aspects of a technical book that readers like to see, but which are often poorly presented. These two aspects are accuracy and a pleasing readability. Readers less skilled in mathematics and interested only in formulae that provide a valid ‘recipe’ like to skip the derivation of that ‘recipe’. In this book this is possible without prejudice to the readability of the story. These ‘recipes’ are framed at the end of formulae derivations. There are readers who are not satisfied with formulae that ‘fall from the sky’ without derivation. For these readers, a ‘recipe’ without substantiation is unsatisfactory and the application of the formulae will be accepted only when the derivation is shown. The formulae are proved in such a way that the reader can easily follow them through, thus a deep knowledge of mathematics is not necessary.

The introduction in chapter 1 will be followed in chapter 2 by the principles of electron emission. Chapters 3, 4, 5 and 6 treat the diode, triode, tetrode and pentode respectively, each with a different framework, but only at middle frequencies and without discussing distortion and negative feedback. Chapter 7 treats the limits of audio frequencies and in chapter 8 are discussions about distortion and noise. Chapter 9 concerns negative feedback and in chapter 10 you can read how to build your own electron tube amplifier. Much of the theory is checked against practice, and design methods give the reader help to start with the design and construction of electron tubes amplifiers.

The aim of the book is to give the reader useful knowledge about electron tube technology in the application of audio amplifiers, including their power supplies, for the design and DIY construction of these electron tube amplifiers. This is much more than just building an electron tube amplifier from a schematic made from the design from someone else: not only academic theory for scientific evidence, but also a theoretical explanation of how the practice works. No modern simulations, but because you first understand the circuit calculations, then you can work with your hands to build the circuit and last, but not least, if you have a multimeter, a signal generator and an oscilloscope, you can measure the circuit parameters yourself to see that theory and practice are very close. That is the aim, and makes this book a unique reference source.

 Table des matières