Table of Contents

1. Setting Goals and Requirements

• 1.1 Output Power
• 1.2 Frequency Range
• 1.3 Power Range
• 1.4 Input Sensitivity and Gain Factor
• 1.5 Damping Factor
• 1.6 Distortion
• 1.7 Interaction

2. The Relationship Between Subjective Perception and Objective Measurements

• 2.1 Directional Hearing
• 2.2 Hearing Details
• 2.3 Tonal Balance
• 2.4 Spatial Depth Imaging
• 2.5 Intermediate Stage
• 2.6 Forward Imaging
• 2.7 Envelopment
• 2.8 Acoustic Structure of the Soundstage
• 2.9 Involvement and Concentration
• 2.10 Summary

3. Circuits and Their Effects

• 3.1 Push-Pull Amplifier
• 3.2 Extensions of Push-Pull Circuits
• 3.3 Characteristic Features of Push-Pull Output Stages
• 3.4 Single-Ended Output Stages
• 3.5 Voltage or Current Control
• 3.6 Alternative Circuit Concepts

4. Considerations for Individual Circuit Components of an Amplifier

• 4.1 Power Supply
• 4.2 Output Stages
• 4.3 Phase Splitter
• 4.4 Driver Stages
• 4.5 Preamplification

5. Amplifier Details

• 5.1 Push-Pull Amplifier
• 5.2 SE Amplifier

6. Negative Feedback

• 6.1 Negative Feedback and Non-linearity
• 6.2 What Voltage is the Amplifier "Busy" With?
• 6.3 How Do Time Delays Affect the Amplification Process?
• 6.4 Negative Feedback Adds Harmonics
• 6.5 Negative Feedback and Timbre Alterations
• 6.6 Negative Feedback and Stability
• 6.7 "Forward-Negative Feedback" (error correction)

7. Building a Prototype

• 7.1 Starting with a Printed Circuit Board Restricts Too Much
• 7.2 Assembly Stations
• 7.3 Grounding
• 7.4 First Operation Without Negative Feedback
• 7.5 Internal Interactions
• 7.6 Logical Construction Concept
• 7.7 Measurements in Individual Stages
• 7.8 Subsequent: Overall Check from Input to Output
• 7.9 Stability
• 7.10 Listening Tests
• 7.11 The Optimization Cycle
• 7.12 What Next?

8. Business Questions

• 8.1 Investment of Time
• 8.2 Investments in Hardware
• 8.3 Sales Channels
• 8.4 Possible Revenue
• 8.5 The Middleman
• 8.6 Timeframes
• 8.7 Developer or Businessman?
• 8.8 Advertising
• 8.9 Highlighting Advantages
• 8.10 Impact on Customers
• 8.11 Service and Customer Support
• 8.12 The Lifespan of a Device and Subsequent Actions
• 8.13 Do I Need a Partner?
• 8.14 Features of the Economy
• 8.15 What is the Competition Doing?
• 8.16 Only Domestically or Worldwide?
• 8.17 Costs
• 8.18 Manufacturing Location
• 8.19 Summary

9. A Holistic Approach

• 9.1 What Does the Heart Say?
• 9.2 Thinking and Acting in Spheres
• 9.3 Your Own Personality
• 9.4 A Challenge

10. Measurements on Amplifiers – Introductory Notes

• 10.1 Analog Measuring Devices
• 10.2 Measurements Using a Computer
• 10.3 Setting Up the Measurement Lab

11. Frequency Response Measurement at 1 Watt

• 11.1 Introductory Notes on the Decibel (dB) Measuring Unit
• 11.2 Measurement Determination of the -3dB Frequency Range

12. Measurement of Frequency Response at Pmax

• 12.1 Push-Pull Output Stage, Pmax, Low-Frequency Range
• 12.2 SE Amplifier, Pmax, Low-Frequency Range
• 12.3 Pmax Limitation at High Frequencies

13. Impedances

• 13.1 Input Impedance
• 13.2 Output Impedance

14. Measuring the Gain Factor

• 14.1 Gain in the Preamplifier Stages
• 14.2 Gain of the Output Stage

15. Distortion

• 15.1 Warning Note!
• 15.2 Analysis of Harmonic Distortion
• 15.3 Intermodulation Distortion
• 15.4 Linearity Measurement

16. Measurements in the Time and Frequency Domain

• 16.1 Phase Measurements
• 16.2 Step Response

17. New Measurement Methods

• 17.1 Brief Review
• 17.2 A New Way?
• 17.3 Thinking Differently!
• 17.4 Which Way Should We Go?

18. Appendix: Can a Tube Amplifier Reproduce Micro-Details?

• 18.1 Introduction
• 18.2 Limits of Our Hearing
• 18.3 Building a Micro-Detail Model
• 18.4 Evidence for the Correctness of the Micro-Detail Model
• 18.5 Influence of the Listening Distance to the Loudspeaker
• 18.6 Influence of the Loudspeaker Efficiency
• 18.7 Influence of the Loudspeaker Frequency Response
• 18.8 Influence of the Primary Impedance Zaa
• 18.9 Influence of Ri,eff
• 18.10 Influence of an Air Gap in the Transformer Core
• 18.11 Influence of the Core Material
• 18.12 Discussion and Conclusions

Glossary

Keyword Index