Guitar Amplifier Electronics Basic Theory book
Guitar Amplifier Electronics

Basic Theory

by Richard Kuehnel
Expected Release Date: August 15, 2018
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Book Description

Over the past century, thousands of books have been written to explain the design of vacuum tube electronics. This new approach uses 21st century technology to provide greater comprehension with less math.

Leo Fender crafted guitar amplifier masterpieces without the assistance of computers, software, or the Internet. For him, "graphical methods" meant drawing load lines with a pencil and ruler. Affordable portable calculators with multiply and divide buttons did not become widespread until the 1970s. In 1973, uprading to a model with a square root button would set you back more than a Pickering cartridge for your Garrard Zero 100SB turntable. Times have changed.

This book presents vacuum tube amplifier theory using modern, web-based design tools and computer visualizations to eliminate the usual litany of mathematical formulas. Each of the book's calculators, available for free on the publisher's website, is designed as a web application that supports today's smart phones, making it as portable as the book itself.

The book begins with the fundamentals of electronics and vacuum tubes. It then proceeds through each stage of a modern guitar amplifier, including preamp voltage amplification stages, tone stacks, power amps, phase inverters, and power supplies. The final chapter is devoted to the craft of controlling overdrive dynamics and harmonic distortion.

ISBN/EAN 978-0-9996742-1-5
Price $29.95
Format paperback
Page Count 179
Publication Date August 15, 2018
Trim Size 7x9 inches
Carton Quantity 14
Subject(s) ARTS & PHOTOGRAPHY : Music : Instruments & Performers

Contents

Introducton

Warning: High Voltage!...1
Less Math, More Understanding...1
Tube Amp Calculators...3
Acknowledgements...5

Chapter 1: Electronics Fundamentals

Electric Charge and Electric Current...6
Work, Voltage, and Power...7
AC and DC Voltages in a Guitar Amp...8
Ohm's Law, Resistors, and Resistance...9
Voltage Dividers...11
Potentiometer Taper...12
Inter-Stage Attenuation in a Preamp...14
Capacitors and Capacitance...15
Decibels and Bode Magnitude Plots...20
Inductors and Inductance...23
Ideal Transformers...26
Real-World Transformers...28

Chapter 2: Vacuum Tubes

The Edison Effect...32
Diodes...33
Triodes...36
Plate Characteristics...37
Transfer Characteristics...38
Plate Resistance, Amplification Factor, and Transconductance...39
Grid Current...42
Multi-Grid Tubes...42
Plate and Screen Current...44
Plate Characteristics...46
Transfer Characteristics...48
Drawing Plate Characteristics for Power Amp Design...49

Chapter 3: Preamps

Voltage Amplification...52
DC Operating Point...54
Cathode Bypass Capacitors...60
AC Load Line...64
Coupling Capacitors...65
Grid-Stopper Resistors...68
Bright Bypass Capacitors...71
Plate Bypass Capacitors...75

Chapter 4: Cathode Followers

Trading Gain for Lower Output Impedance...76
DC Coupling...81

Chapter 5: Tone Stacks

The Bassman 5F6-A and JMP50 Model 1987 Stack...84
How It Works...84
Modifications...88
Potentiometer Taper...88
Driving the Stack Directly from a Voltage Amplifier...89
The James Stack...91
Orange OR120 (Graphic Mk II)...91
Fender Twin 5D8...94
Tone Shaping - The Big Picture...96

Chapter 6: Power Amps

A Transformer in the Plate Circuit...98
Single-Ended Design...101
Learning from a 6L6GC Data Sheet...102
A 6L6 Single-Ended Design...105
Parallel Design...109
Push-Pull Design...110
Basic Concepts...110
A 6V6 Push-Pull Fixed-Bias Design...113
Converting to Cathode Bias...115
Power Supply Voltage Sag...116
Wrapping Up the Designs...118
Grid-Leak Resistors...120

Chapter 7: Phase Inverters

Paraphase...122
Concertina/Cathodyne/Split-Load...126
Long-Tailed Pair - How It Works...130
Long-Tailed Pair - A Design Procedure...133

Chapter 8: Negative Feedback

Generalized Concept for Guitar Amplifiers...140
Single-Ended Design...141
Long-Tailed-Pair Design...143
Final Comments on Negative Feedback...146

Chapter 9: Power Supplies

Transformer Considerations...148
Rectifiers and DC Voltage Sag...150
Ripple Filtering and Decoupling...154
Negative Bias Supplies...155

Chapter 10: Overdrive and Harmonic Distortion

Grid Current Effects...158
Bias Excursion...160
Harmonic Distortion...163
Mesa/Boogie Mark I Overdrive Harmonics...167
Push-Pull and Negative Feedback Effects...170

Some Final Words on Guitar Amplifier Design...172

Index...174