Introduction 5

Chapter 1. Audio amplification basics and parameters 18
Audio amplification path 18
High quality Power Amps 19
Power Amps applications 20
Input requirements 22
Load 23
Frequency range 24
Distortion 26
Damping factor 27
Noise 29
Output power and efficiency 31
Phase parameters 33
Reliability 34

Chapter 2. Sound and others 39
Subjectivity, science and sound 39
Practice and performance criteria 45
Tubes vs transistors 48
Market extravagancy 52

Chapter 3. Power amps circuit design 56
Basic structural diagrams 56
Negative feedback 61
Typical Lin's circuit 65
Low frequency range 66
Current sources 67
Input differential stage 72
Current mirror 76
Voltage gain stage 79
Slew rate and dynamic linearity criteria 92
Output stage 100
Scheme with parallel channel 144

Chapter 4. Audio Power Amps sub-assemblies 148
Fuses 148
Output stage protection 149
Speaker protection circuits 161
Audio power supplies 168

Chapter 5. Audio Power Amps examples 173
Entry-level Power Amps 173
Stage audio Power Amps 224
High quality Power Amps 233
Precision Power Amps 245

Chapter 6. Integral OpAmps for sound 253
National Semiconductor products 253
Signetics/TI products 261
Linear Technology products 270
ADI products 281
Burr-Brown/TI products 293
OpAmp with differential parallel channel 309

Chapter 7. Audio Power Amps fabrication and testing 318
PCB fabrication 318
Electrical safety 319
Test and measuring equipment 320
Power Amps testing 321
Operation verification and quiescent current setting 329
Troubleshooting 331
Load capacity testing 333

Afterword 335

Appendix A. PCB drawings 336

Appendix B. Materials and components sources 348

References 349

Index 350