Valve Amplifiers


  • Morgan Jones

Valve Amplifiers has been recognized as the most comprehensive guide to valve amplifier design, analysis, modification and maintenance. It provides a detailed presentation of the rudiments of electronics and valve design for engineers and non-experts. The source also covers design principles and construction techniques to help end users build their own tool from scratch designs that work. The author's approach walks the reader through each step of designing and constructing, starting with an overview of the essential working principles of valve amplifiers, the simple and complex stages, the process of linking the stages, and completing the design. The book is comprised of seven chapters all of which include a DIY guide discussion of practical aspects. The text starts with familiarization of the fundamentals of electronics, which are essential for designing and building valve amplifiers. Particular attention has been paid to providing solutions for questions that are commonly asked and faced by beginners in valve designing and construction. Valve Amplifiers is a masterful hands-on guide for both experts and novices who work with tube audio equipment, and for electronic hobbyists, audio engineers, and audiophiles.
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Amateur and professional valve audio designers and enthusiasts.


Book information

  • Published: November 2011
  • Imprint: NEWNES
  • ISBN: 978-0-08-096640-3


"Jam-packed with theory, circuit analysis, and DIY basics, it will walk you through all stages of design so that you can create your own wonders. Jones is an ex-BBC engineer with a cool writing style and you'll find it a no-pain education." Hi-Fi News and Record Review "Valve Amplifiers is an extremely well-written book, containing a wealth of information that all audio designers and builders will find useful." Glass Audio "Many still hanker after the traditional warm valve sound from a hi-fi, and if you're handy with a soldering iron and not afraid of HT voltages, the Jones' book could keep you amused for hours. Filled with designs, tips, and information on every aspect of valve power amplifiers, a basic knowledge of electronics and metalwork is all you'll need to get the most from this (relatively) ancient technology." Lighting & Sound

Table of Contents




1. Circuit Analysis

    Mathematical Symbols

    Electrons and Definitions

    Potential Dividers

    Alternating Current (AC)

    Active Devices

    Silicon Diodes

    Bipolar Junction Transistors (BJTs)

    General Observations on BJTs


    The Operational Amplifier


    Recommended Further Reading

2. Basic Building Blocks

    The Common Cathode Triode Amplifier

    The Tetrode

    The Beam Tetrode and the Pentode

    The Cascode

    The Charge Amplifier

    The Cathode Follower

    Sources and Sinks: Definitions

    The Common Cathode Amplifier as a Constant Current Sink (CCS)

    The Cathode Follower with Active Load

    The White Cathode Follower

    The μ-follower

    The Shunt-Regulated PushPull Amplifier (SRPP)

    The β-follower

    The Cathode-Coupled Amplifier

    The Differential Pair

    Semiconductor Constant Current Sinks


    Recommended Further Reading

3. Dynamic Range: Distortion and Noise


    Digital Concepts

    The Fast Fourier Transform (FFT)

    Designing for Low Distortion

    Signal Amplitude

    Grid Current

    Distortion Reduction by Parameter Restriction

    Distortion Reduction by Cancellation

    DC Bias Problems

    Individual Valve Choice

    Coupling from One Stage to the Next

    Distortion and Negative Feedback

    Carbon Resistors and Distortion


    Noise from Resistances

    Noise from Amplifying Devices

    Noise in DC References


    Recommended Further Reading

4. Component Technology


    General Considerations on Choosing Resistors


    Different Types of Capacitors

    General Considerations in Choosing Capacitors

    Magnetic Components



    Why Should I Use a Transformer?

    General Considerations in Choosing Transformers

    Uses and Abuses of Audio Transformers

    Thermionic Valves

    Individual Elements of the Valve Structure


    Recommended Further Reading

5. Power Supplies

    The Major Blocks

    Rectification and Smoothing


    Common-Mode Interference

    Practical Issues

    A Practical Design

    Adapting the Power Supply to the EC8010 RIAA Stage


    Recommended Further Reading

6. The Power Amplifier

    The Output Stage

    Classes of Amplifiers

    The PushPull Output Stage and the Output Transformer

    Output Transformer-Less (OTL) Amplifiers

    The Entire Amplifier

    The Driver Stage

    The Phase Splitter

    The Input Stage


    Classic Power Amplifiers

    New Designs

    Single-Ended Madness

    The Scrapbox Challenge Single-Ended Amplifier

    Obtaining More Than Single Digit Output Power

    Driving Higher Power Output Stages

    The Crystal Palace Amplifier

    The Bulwer-Lytton Scalable Parallel PushPull Amplifier


    Further Reading

7. The Pre-Amplifier

    Input Selection

    Volume Control

    Balance Control

    Cable Driver

    Tone Control

    Obtaining a Clean Signal from Analogue Disc

    RIAA Stage Design

    A Simplified Example RIAA Stage

    The EC8010 RIAA Stage

    The Balanced Hybrid RIAA Stage


    Recommended Further Reading


    Valve Data

    Standard Component Values

    Resistor Colour Code

    Plastic Capacitor Coding


    Square Wave Sag and Low Frequency f-23 dB

    Playing 78s



    Sourcing Components: Bargains and Dealing Directly