Valve and Transistor Audio Amplifiers (eBook)

Cover 
1 
Contents 6
Preface 10
Chapter 1. Active Components 14
Valves or Vacuum Tubes 14
Solid State Devices 24
Chapter 2. Passive Components 38
Inductors and Transformers 38
Capacitors 43
Resistors 49
Switches and Electrical Contacts 52
Chapter 3. Voltage Amplifier Stages Using Valves 54
Circuit Configurations 54
Grid Bias Systems 54
Cathode Bias Resistor Calculations 58
Anode Load Systems 58
Grounded Grid Stages 60
The Cascode Circuit 61
The Long-tailed Pair 61
The Cathode Follower 62
The µ Follower 63
Tetrodes, Beam-Tetrodes and Pentodes 63
Load Lines 66
Chapter 4. Valve Audio Amplifier Layouts 70
Single-ended vs. Push–pull Operation 72
Phase Splitters 74
Output Stages 77
Output (Load-matching) Transformer 78
Effect of Output Load Impedance 81
Available Output Power 82
Chapter 5. Negative Feedback 84
Benefits of Negative Feedback 86
Stability Problems 87
Series and Shunt NFB 88
The Effect of NFB on Input and Output Impedances 90
Influence of NFB on Output Impedance 93
Effect of NFB on the Harmonic Components of the Signal 94
Practical Valve NFB Systems 95
The Baxandall Negative Feedback Tone Tontrol System 96
Frequency Response Equalisation 98
Filter Circuits Based on NFB 99
Chapter 6. Valve Operated Audio Power Amplifiers 106
The Mclntosh Amplifier 107
The Williamson Amplifier 108
Distributed Load Systems 111
The Quad System 112
Baxandall's Amplifier 114
The Baxandall 5 Watt Design 117
The Radford Valve Amplifiers 118
The Leak TL/12 119
The Mullard 5/10 and 5/20 Designs 119
The GEC Audio Amplifiers 120
The GEC 912 + Amplifier 122
Other GEC Audio Designs 123
The Brimar 25P1 Design 123
The Sonab Design 125
Increasing Available Output Power 126
Conclusions 128
Chapter 7. Solid State Voltage Amplifiers 130
Junction Transistors 130
Control of Operating Bias 132
Stage Gain 134
Basic Junction Transistor Circuit Configurations 135
Emitter–follower Systems 137
Thermal Dissipation Limits 139
Junction Field Effect Transistors (JFETs) 140
Insulated Gate FETs (MOSFETs) 144
Power BJTs vs. Power MOSFETs as Amplifier Output Devices 147
U and D MOSFETs 148
Useful Circuit Components 150
Circuit Oddments 151
Slew Rate Limiting 153
Chapter 8. Early Solid State Audio Amplifier Designs 154
The Lin Circuit 156
Quasi-complementary Output Stage Asymmetry 158
Listener Fatigue 161
Alternative Circuit Choices 163
Class A Operation 166
Fully Complementary Designs 169
Gain Stage Designs 171
HF Compensation Techniques 173
Symmetry in Circuit Layout and Slewing Rates 175
Stability of Output Current 176
Chapter 9. Contemporary Power Amplifier Designs 180
Remaining Design Problems 180
Power MOSFETs vs. Bipolar Junction Power Ttransistors (BJTs) 181
Frequency Response of MOSFET Devices 182
MOSFET Linearity 184
gm Values for BJTs and MOSFETs 187
Quiescent Current Stability in Push–pull Output Systems 188
Other Iq Control Techniques 189
The Quad Current Dumping Amplifier 191
The Sandman Class S System 193
The Technics Class AA system 193
Voltage Amplifying Stage Gain and Overall THD 194
Basic Gain Stage Constructions 195
Output/Input Signal Isolation 199
Effect of NFB on Signal Distortion 200
Symmetry in Gain Block Structure 200
Negative Feedback and Sound Quality 201
Power Amplifier Output Stages 203
Output DC Offset Control 204
Hybrid Systems 206
Listening Trials 206
Chapter 10. Preamplifiers 210
Gramophone Record Replay Equalisation Characteristics 211
Replay Equalisation Circuitry 212
Practical Circuit Layouts 216
Very Low Noise Input Systems 219
Low Noise Devices 222
Headroom 225
Tone Controls and Filters 228
Signal Channel Switching and Remote Controls 231
Voltage Controlled Gain Systems 232
Digital Inputs 234
Chapter 11. Power Supplies 238
High Power Systems 238
Solid State Rectifiers 239
Music Power 242
Influence of Signal Type on Power Supply Design 242
High Current Power Supply Systems 243
Half-wave and Full-wave Rectification 244
DC Supply Line Ripple Rejection 245
Voltage Regulator Systems 245
Series Regulator Layouts 246
Over-current Protection 247
Integrated Circuit (Three Terminal) Voltage Regulator ICs 249
Typical Contemporary Commercial Practice 252
Battery Supplies 252
Switch-mode Power Supplies 254
Index 256