Valve
Amplifiers
by Morgan Jones
Table of Contents
CHAPTER 1. Circuit Analysis;
Mathematical symbols
Electrons and definitions
Potential dividers
Alternating current
Active devices
Silicon diodes
Bipolar Junction Transistors (BJTs)
Feedback
The operational amplifier
CHAPTER 2. Basic Building Blocks;
The common cathode triode amplifier
The tetrode
The beam tetrode and pentode
The cascode
The cathode follower
Sources and sinks: definitions
The common cathode amplifier as a constant current sink
The cathode follower with active load
The White cathode follower
The µ-follower
The Shunt Regulated Push-Pull (SRPP) amplifier
The β-follower
The differential pair
Semiconductor constant current sinks
CHAPTER 3. Distortion;
Defining distortion
Digital concepts
The Fast Fourier Transform (FFT)
Designing for low distortion
The AC operating point
The DC operating point
Distortion reduction by parameter restriction
Distortion reduction by cancellation
DC bias problems
Individual valve choice
Coupling from one stage to the next
CHAPTER 4. Component Technology;
Resistors
General considerations on choosing resistors
Capacitors
Different types of capacitors
General considerations in choosing capcitors
Magnetic components
Inductors
Transformers
Why should I choose a transformer?
General considerations in choosing a transformer
Use and abuses of audio transformers
Thermionic valves
Individual elements of the valve structure
CHAPTER 5. Power Supplies;
The major blocks
Rectification and smoothing
Regulators
A practical design
Specification of the power supply
A better power supply
CHAPTER 6. The Power Amplifier;
The output stage
Classes of amplifiers
The push-pull out stage and the output transformer
Output Transformer-Less (OTL) amplifiers
The entire amplifier
The driver stage
The phase splitter
The input stage
Stability
Classic power amplifiers
The Williamson
The Mullard 5-20
The Quad II
New designs
Single-ended madness
The "Scrapbox Challenge" single-ended amplifier
HT choke suitability
Push-pull sanity
The "Bevois Valley" amplifier
The author's prototypes
The traditional approach to power >10W
Driving higher power output stages
The "Crystal Palace" amplifier
"Daughter of the Beast"
CHAPTER 7. The Pre-Amplifier
The line stage
The volume control
Input selectors
The RIAA disc stage
Noise and input capacitance of the input stage
Strays and implementing RIAA
Basic pre-amplifier compromises
A balanced pre-amplifier
The perfect line stage
The EC8010 RIAA stage
Achieving the RIAA equalization
Practical RIAA considerations
A line stage
APPENDIX. Valve Data
Square wave sag and low frequency f-3db
Playing 78s
Equalization
Standard component values
Resistor colour code
Sallen & Key filters for active crossovers
UK sources of components
Bargains and dealing directly