Guitar Amplifier Electronics: Basic Theory is a new approach to explaining how to design the essential circuits of a vacuum tube guitar amplifier, including preamps, cathode followers, tone stacks, power amps, phase inverters, negative feedback, and power supplies.
The book includes the traditional mathematical formulas for calculating parts values that were used by legendary amp designers like Leo Fender, Jim Marshall, and Dave Reeves.
Its primary design tools, however, are modern graphing calculators that are free on our website.
They are designed for smartphones and laptops, making them as portable as the book that puts them through their paces.
Richard Kuehnel
is a member of the Circuits and Systems Society of the Institute of Electrical and Electronic Engineers.
| |
 |
 |
 |
 |
 |
 |
| Mastering Basic Electronics |
✓ |
|
|
|
|
|
| Preamps and Tone Stacks |
✓ |
✓ |
✓ |
✓ |
✓ |
✓ |
| Power Amps and Negative Feedback |
✓ |
✓ |
✓ |
✓ |
✓ |
✓ |
| Power Supplies |
✓ |
✓ |
✓ |
✓ |
✓ |
✓ |
| DC-Coupled Cathode Followers |
✓ |
✓ |
|
|
✓ |
✓ |
| Effects Loops |
|
✓ |
|
|
|
✓ |
| Reverb and Tremolo |
|
|
|
✓ |
|
|
| |
|
|
|
|
|
|
| Crafting a Complete Architecture |
|
✓ |
|
|
|
|
| Testing Overdrive Dynamics |
|
|
✓ |
|
|
|
| Measuring Distortion |
|
|
✓ |
✓ |
✓ |
✓ |
Introduction
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
