Amplificador

Audio Power Amplifier Design Handbook

Audio Power Amplifier Design Handbook
Third edition

Douglas Self MA, MSc

Newnes
PARIS OXFORD AMSTERDAM BOSTON LONDON NEW YORK SAN DIEGO SAN FRANCISCO SINGAPORE SYDNEY TOKYO

Newnes An imprint of Elsevier Science Linacre House, Jordan Hill, Oxford OX2 8DP 225 Wildwood Avenue, Woburn MA 01801-2041 First published 1996 Reprinted 1997, 1998Second edition 2000 Reprinted 2000 Third edition 2002 Copyright © 1996, 2000, 2002, Douglas Self. All rights reserved The right of Douglas Self to be identified as the author of this work has been asserted in accordance with the Copyright, Designs and Patents Act 1988
No part of this publication may be reproduced in any material form (including photocopying or storing in any medium by electronic meansand whether or not transiently or incidentally to some other use of this publication) without the written permission of the copyright holder except in accordance with the provisions of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London, England W1T 4LP. Applications for the copyright holder’swritten permission to reproduce any part of this publication should be addressed to the publisher

British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library ISBN 0 7506 56360

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Contents
Synopsis Preface 1. Introduction and general survey 2. History, architecture and negative feedback 3. The general principles of power amplifiers 4. The small signal stages 5. The output stage I 6. The output stage II 7. Compensation, slew-rate, and stability 8. Power supplies and PSRR 9. Class-A power amplifiers 10. Class-G power amplifiers 11. FET output stages 12.Thermal compensation and thermal dynamics 13. Amplifier and loudspeaker protection 14. Grounding and practical matters 15. Testing and safety Index vii xv 1 30 60 73 106 163 183 235 255 290 314 325 370 396 418 423

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Synopsis
Chapter 1 Introduction and general survey
The economic importance of audio amplifiers There are no practical textbooks Knowledge assumed Origins and aims The study ofamplifier design Some new findings in amplifier design A snapshot of the technology No inspiration from IC technology Aimed at discrete amplifiers Amplifiers are now designable Misinformation in audio Science and subjectivism The Subjectivist position A short history of subjectivism The limits of hearing Articles of faith: the tenets of subjectivism The length of the audio chain The implications Thereasons why The outlook Technical errors The performance requirements for amplifiers Safety Reliability Power output and load capability Frequency response Noise Distortion Damping factor Absolute phase Acronyms

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Synopsis

Chapter 2 History, architecture and negative feedback
A Brief History of Power Amplifiers Power amplifier architectures The three-stage structure The two-stageamplifier structure Power amplification classes Class-A Class-AB Class-B Class-C Class-D Class-E Class-F Class-G Class-H Class-S Variations on Class-B AC and DC coupled amplifiers The advantages of AC-coupling The advantages of DC-coupling Negative feedback in power amplifiers Some common misconceptions about negative feedback Amplifier stability and NFB Maximising the NFB factor Linearising beforeadding NFB

Chapter 3 The general principles of power amplifiers
How a generic power amplifier really works The advantages of the conventional The eight distortions The performance of a standard power amplifier Determining open-loop non-linearity Direct open-loop gain measurement The use of ‘model’ amplifiers The concept of the Blameless amplifier

Chapter 4 The small signal stages
The role...