Small signal audio design

Cover
Half Title
Title
Copyright
Dedication
Contents
Preface
Acknowledgments
Chapter 1 The Basics
	Signals
	Amplifiers
		Voltage Amplifiers
		Transconductance Amplifiers
		Current Amplifiers
		Transimpedance Amplifiers
	Negative Feedback
	Nominal Signal Levels and Dynamic Range
	Frequency Response
		Frequency Response: Cascaded Stages
	Phase Perception
	Gain Structures
		Amplification Then Attenuation
		Attenuation Then Amplification
		Raising the Input Signal to the Nominal Level
		Active Gain Controls
	Noise
	Johnson Noise
	Shot Noise
	1/f Noise (Flicker Noise)
	Popcorn Noise
	Summing Noise Sources
	Noise in Amplifiers
	Noise in Bipolar Transistors
		Bipolar Transistor Voltage Noise
		Bipolar Transistor Current Noise
	Noise in JFETs
		Noise in Opamps
	Noise Gain
	Low-Noise Opamp Circuitry
	Noise Measurements
	How to Attenuate Quietly
	How to Amplify Quietly
	How to Invert Quietly
	How to Balance Quietly
	Ultra-Low-Noise Design With Multi-Path Amplifiers
		Ultra-Low-Noise Voltage Buffers
		Ultra-Low-Noise Amplifiers
	Multiple Amplifiers for Greater Drive Capability
Chapter 2 Components
	Conductors
		Copper and Other Conductive Elements
		The Metallurgy of Copper
		Gold and Its Uses
		Cable and Wiring Resistance
		PCB Track Resistance
	PCB Track-to-Track Crosstalk
	The Three-Layer PCB
	Impedances and Crosstalk: A Case History
	Resistors
		Through-Hole Resistors
		Surface-Mount Resistors
		Resistor Series
		Resistor Accuracy: Two-Resistor Combinations
		Resistor Accuracy: Three-Resistor Combinations
		Other Resistor Combinations
		Resistor Value Distributions
		The Uniform Distribution
		Resistor Imperfections
		Resistor Excess Noise
		Resistor Non-Linearity
	Capacitors
		Capacitor Series
		Capacitor Non-Linearity Examined
		Non-Electrolytic Capacitor Non-Linearity
		Electrolytic Capacitor Non-Linearity
	Inductors
Chapter 3 Discrete Transistor Circuitry
	Why Use Discrete Transistor Circuitry?
	Bipolars and FETs
	Bipolar Junction Transistors
	The Transistor Equation
	Beta
	Unity-Gain Buffer Stages
		The Simple Emitter-Follower
		The Constant-Current Emitter-Follower
		The Push-Pull Emitter-Follower
		Emitter-Follower Stability
		CFP Emitter-Followers
		Improved Unity-Gain Buffers
	Gain Stages
		One-Transistor Shunt-Feedback Gain Stages
		One-Transistor Series-Feedback Gain Stages
		Two-Transistor Shunt-Feedback Gain Stages
		Two-Transistor Shunt-Feedback Stages: Improving Linearity
		Two-Transistor Shunt-Feedback Stages: Noise
		Two-Transistor Shunt-Feedback Stages: Bootstrapping
		Two-Transistor Shunt-Feedback Stages as Summing Amplifiers
		Two-Transistor Series-Feedback Gain Stages
	Discrete Opamp Design
		Discrete Opamp Design: The Input Stage
		Discrete Opamp Design: The Second Stage
		Discrete Opamp Design: The Output Stage
	High-Input-Impedance Bipolar Stages
Chapter 4 Opamps and Their Properties
	Introduction
	A Very Brief History of Opamps
	Opamp Properties: Noise
	Opamp Properties: Slew Rate
	Opamp Properties: Common Mode Range
	Opamp Properties: Input Offset Voltage
	Opamp Properties: Bias Current
	Opamp Properties: Cost
	Opamp Properties: Distortion
		Opamp Internal Distortion
		Slew-Rate Limiting Distortion
		Distortion Due to Loading
		Thermal Distortion
		Common-Mode Distortion
		Common-Mode Distortion: Bipolar Input Opamps
		Common-Mode Distortion: JFET Opamps
	Selecting the Right Opamp
	Opamps Surveyed: BJT Input Types
		The LM741 Opamp
	The NE5532/5534 Opamp
		Deconstructing the 5532
		The LM4562 Opamp
		The AD797 Opamp
		The OP27 Opamp
		The OP270 Opamp
		The OP275 Opamp
	Opamps Surveyed: JFET Input Types
		The TL072 Opamp
		The TL052 Opamp
		The OPA2134 Opamp
		The OPA604 Opamp
		The OPA627 Opamp
Chapter 5 Opamps for Low Voltages
	High Fidelity From Low Voltages
	Running Opamps From a Single +5 V Supply Rail
	Opamps for 5 V Operation
	The NE5532 in +5 V Operation
	The LM4562 in +5 V Operation
	The AD8022 in +5 V Operation
	The AD8397 in +5 V Operation
	Opamps for 3.3 V Single-Rail Operation
Chapter 6 Filters
	Introduction
	Passive Filters
	Active Filters
	Low-Pass Filters
	High-Pass Filters
	Combined Low-Pass and High-Pass Filters
	Band-Pass Filters
	Notch Filters
	All-Pass Filters
	Filter Characteristics
	Sallen and Key Low-Pass Filters
	Sallen and Key High-Pass Filters
	Distortion in Sallen and Key Filters
	Multiple-Feedback Band-Pass Filters
	Notch Filters
	Differential Filters
Chapter 7 Preamplifier Architectures
	Passive Preamplifiers
	Active Preamplifiers
	Amplification and the Gain-Distribution Problem
	Active Gain Controls
	Active Gain Controls Plus Passive Attenuators
	Recording Facilities
	Tone Controls
Chapter 8 Variable Gain Stages
	Amplifier Stages With Gain From Unity Upwards: Single-Gain Pot
	Amplifier Stages With Gain From Unity Upwards: Dual-Gain Pot
	Combining Gain Stages With Active Filters
	Amplifier Stages With Gain From Zero Upwards: Single-Gain Pot
	Amplifier Stages With Gain From Zero Upwards: Dual-Gain Pot
	Switched-Gain Amplifiers
Chapter 9 Moving-Magnet Inputs: Levels and RIAA Equalisation
	Cartridge Types
	The Vinyl Medium
	Spurious Signals
	Other Vinyl Problems
	Maximum Signal Levels From Vinyl
	Moving-Magnet Cartridge Sensitivities
	Overload Margins and Amplifier Limitations
	Equalisation and Its Discontents
	The Unloved IEC Amendment
	The “Neumann Pole”
	MM Amplifier Configurations
	Opamp MM Input Stages
	Calculating the RIAA Equalisation Components
	Implementing RIAA Equalisation
	Implementing the IEC Amendment
	RIAA Series-Feedback Network Configurations
	RIAA Optimisation: C1 as a Single E6 Capacitor, 2xE24
	RIAA Optimisation: C1 as 3 x 10 nF Capacitors, 2xE24
	RIAA Optimisation: C1 as 4 x 10 nF Capacitors, 2xE24
	RIAA Optimisation: The Willmann Tables
	RIAA Optimisation: C1 as 3 x 10 nF Capacitors, 3xE24
	RIAA Optimisation: C1 as 4 x 10 nF Capacitors, 3xE24
	Switched-Gain MM RIAA Amplifiers
	Switched-Gain MM/MC RIAA Amplifiers
	Open-Loop Gain and RIAA Accuracy
	Passive and Semi-Passive RIAA Equalisation
	MM Cartridge Loading and Frequency Response
	MM Cartridge–Preamplifier Interaction
	MM Cartridge DC and AC Coupling
	Noise in MM RIAA Preamplifiers
	Hybrid MM Amplifiers
	Balanced MM Inputs
	Noise in Balanced MM Inputs
	Noise Weighting
	Noise Measurements
	Cartridge Load Synthesis for Lower Noise
	Subsonic Filters
		Subsonic Filtering: Butterworth Filters
		Subsonic Filtering: Elliptical Filters
		Subsonic Filtering by Cancellation
	Ultrasonic Filters
	A Practical MM Amplifier #3
Chapter 10 Moving-Coil Head Amplifiers
	Moving-Coil Cartridge Characteristics
	The Limits on MC Noise Performance
	Amplification Strategies
	Moving-Coil Transformers
	Moving-Coil Input Amplifiers
	An Effective MC Amplifier Configuration
	The Complete Circuit
	Performance
Chapter 11 Tape Replay
	The Return of Tape
	A Brief History of Tape Recording
	The Basics of Tape Recording
	Multi-Track Recording
	Tape Heads
	Tape Replay
	Tape Replay Equalisation
	Tape Replay Amplifiers
	Replay Noise: Calculation
	Replay Noise: Measurements
	Load Synthesis
	Noise Reduction Systems
	Dolby HX-Pro
Chapter 12 Guitar Preamplifiers
	Electric Guitar Technology
	Guitar Pickups
	Pickup Characteristics
	Guitar Wiring
	Guitar Leads
	Guitar Preamplifiers
	Guitar Preamplifier Noise: Calculations
	Guitar Preamplifier Noise: Measurements
	Guitar Amplifiers and Guitar Effects
	Guitar Direct Injection
Chapter 13 Volume Controls
	Volume Controls
	Volume Control Laws
	Loaded Linear Pots
	Dual-Action Volume Controls
	Tapped Volume Controls
	Slide Faders
	Active Volume Controls
	The Baxandall Active Volume Control
	The Baxandall Volume Control Law
	A Practical Baxandall Active Volume Stage
	Low-Noise Baxandall Active Volume Stages
	The Baxandall Volume Control: Loading Effects
	An Improved Baxandall Active Volume Stage With Lower Noise
	Baxandall Active Volume Stage Plus Passive Control
	The Overlap Penalty
	Potentiometers and DC
	Belt-Ganged Volume Controls
	Motorised Potentiometers
	Stepped Volume Controls
	Switched Attenuator Volume Controls
	Relay-Switched Volume Controls
	Transformer-Tap Volume Controls
	Integrated Circuit Volume Controls
	Loudness Controls
	The Newcomb and Young Loudness Control
Chapter 14 Balance Controls
	The Ideal Balance Law
	Balance Controls: Passive
	Balance Controls: Active
	Combining Balance Controls With Other Stages
	Switched Balance Controls
	Mono-Stereo Switches
	Width Controls
Chapter 15 Tone Controls and Equalisers
	Introduction
	Passive Tone Controls
	Baxandall Tone Controls
		The Baxandall One-LF-Capacitor Tone Control
		The Baxandall Two-LF-Capacitor Tone Control
		The Baxandall Two-HF-Capacitor Tone Control
		The Baxandall Tone Control: Impedance and Noise
		Combining a Baxandall Stage With an Active Balance Control
		Switched-HF-Frequency Baxandall Controls
	Variable-Frequency HF EQ
	Variable-Frequency LF EQ
	A New Type of Switched-Frequency LF EQ
	Variable-Frequency HF and LF EQ in One Stage
	Tilt or Tone-Balance Controls
	Middle Controls
		Fixed Frequency Baxandall Middle Controls
		Three-Band Baxandall EQ in One Stage
		Wien Fixed Middle EQ
		Wien Fixed Middle EQ: Altering the Q
		Variable-Frequency Middle EQ
		Single-Gang Variable-Frequency Middle EQ
		Switched-Q Variable-Frequency Wien Middle EQ
	Switchable Peak/Shelving LF/HF EQ
	Parametric Middle EQ
	Graphic Equalisers
Chapter 16 Mixer Architecture
	Introduction
	Performance Factors
	Mixer Internal Levels
	Mixer Architecture
	The Split Mixing Architecture
	The In-Line Mixing Architecture
	A Closer Look at Split-Format Modules
		The Channel Module (Split Format)
		Effect Return Modules
		The Group Module
		The Master Module
		Talkback and Oscillator Systems
	The In-Line Channel Module
Chapter 17 Microphone Preamplifiers
	Microphone Types
	Microphone Preamplifier Requirements
	Transformer Microphone Inputs
	The Simple Hybrid Microphone Preamplifier
	The Balanced-Feedback Hybrid Microphone Preamplifier (BFMA)
	Microphone and Line Input Pads
	The Padless Microphone Preamplifier
	Capacitor Microphone Head Amplifiers
	Ribbon Microphone Amplifiers
Chapter 18 Line Inputs
	External Signal Levels
	Internal Signal Levels
	Input Amplifier Functions
	Unbalanced Inputs
	Balanced Interconnections
	The Advantages of Balanced Interconnections
	The Disadvantages of Balanced Interconnections
	Balanced Cables and Interference
	Balanced Connectors
	Balanced Signal Levels
	Electronic Versus Transformer Balanced Inputs
	Common Mode Rejection
		The Basic Electronic Balanced Input
		The Basic Balanced Input and Opamp Effects
	Opamp Frequency Response Effects
	Opamp CMRR Effects
	Amplifier Component Mismatch Effects
	A Practical Balanced Input
	Variations on the Balanced Input Stage
		Combined Unbalanced and Balanced Inputs
		The Superbal Input
		Switched-Gain Balanced Inputs
		Variable-Gain Balanced Inputs
		Combined Line Input and Balance Control Stage With Low Noise
		The Self Variable-Gain Line Input
		High Input-Impedance Balanced Inputs
		The Inverting Two-Opamp Input
		The Instrumentation Amplifier
		Instrumentation Amplifier Applications
		The Instrumentation Amplifier With 4x Gain
		The Instrumentation Amplifier at Unity Gain
		The Instrumentation Amplifier and Gain Controls
		The Instrumentation Amplifier and the Whitlock Bootstrap
	Transformer Balanced Inputs
	Input Overvoltage Protection
	Low-Noise Balanced Inputs
	Low-Noise Balanced Inputs in Action
	Ultra-Low-Noise Balanced Inputs
Chapter 19 Line Outputs
	Unbalanced Outputs
	Zero-Impedance Outputs
	Ground-Cancelling Outputs: Basics
	Ground-Cancelling Outputs: Zero-Impedance Output
	Ground-Cancelling Outputs: CMRR
	Ground-Cancelling Outputs: Send Amplifier Noise
	Ground-Cancelling Outputs: Into a Balanced Input
	Ground-Cancelling Outputs: History
	Balanced Outputs: Basics
	Balanced Outputs: Output Impedance
	Balanced Outputs: Noise
	Quasi-Floating Outputs
	Transformer Balanced Outputs
	Output Transformer Frequency Response
	Output Transformer Distortion
	Reducing Output Transformer Distortion
Chapter 20 Headphone Amplifiers
	Driving Heavy Loads
	Driving Headphones
	Special Opamps
	Multiple Opamps
	Opamp-Transistor Hybrid Amplifiers
	Discrete Class-AB Headphone Amplifiers
	Discrete Class-A Headphone Amplifiers
		Gain
		Maximum Output
		Noise Performance
		Power Consumption
	Balanced Headphone Amplifiers
Chapter 21 Signal Switching
	Mechanical Switches
	Input-Select Switching: Mechanical
	The Virtual Contact: Mechanical
	Relay Switching
	Electronic Switching
	Switching with CMOS Analogue Gates
		CMOS Gates in Voltage Mode
		CMOS Gates in Current Mode
		CMOS Series-Shunt Current Mode
		Control Voltage Feedthrough in CMOS Gates
		CMOS Gates at Higher Voltages
		CMOS Gates at Low Voltages
		CMOS Gate Costs
	Discrete JFET Switching
		The Series JFET Switch in Voltage Mode
		The Shunt JFET Switch in Voltage Mode
		JFETs in Current Mode
		Reducing Distortion by Biasing
		JFET Drive Circuitry
		Physical Layout and Offness
		Dealing With the DC Conditions
		A Soft Changeover Circuit
		Control Voltage Feedthrough in JFETS
Chapter 22 Mixer Sub-Systems
	Mixer Bus Systems
	Input Arrangements
	Equalisation
	Insert Points
	How to Move a Circuit Block
	Faders
		Improving Fader Offness
	Post-Fade Amplifiers
	Direct Outputs
	Panpots
		Passive Panpots
		The Active Panpot
		LCR Panpots
	Routing Systems
	Auxiliary Sends
	Group Module Circuit Blocks
	Summing Systems: Voltage Summing
	Summing Systems: Virtual-Earth Summing
	Balanced Summing Systems
	Ground-Cancelling Summing Systems
	Distributed Summing Systems
	Summing Amplifiers
	Hybrid Summing Amplifiers
	Balanced Hybrid Summing Amplifiers
	Balancing Tracks to Reduce Crosstalk
	The Multi-Function Summing Amplifier
	PFL Systems
		PFL Summing
		PFL Switching
		PFL Detection
		Virtual-Earth PFL Detection
	AFL Systems
	Solo-in-Place Systems
	Talkback Microphone Amplifiers
	Line-Up Oscillators
	The Flash Bus
	Power Supply Protection
	Console Cooling and Component Lifetimes
Chapter 23 Level Indication and Metering
	Signal-Present Indication
	Peak Indication
	The Log Law Level LED (LLLL)
	Distributed Peak Detection
	Combined LED Indicators
	VU Meters
	PPMs
	LED Bar-Graph Metering
	A More Efficient LED Bar-Graph Architecture
	Vacuum Fluorescent Displays
	Plasma Displays
	Liquid Crystal Displays
Chapter 24 Level Control and Special Circuits
	Gain-Control Elements
		A Brief History of Gain-Control Elements
		JFETs
		Operational Transconductance Amplifiers (OTAs)
		Voltage-Controlled Amplifiers (VCAs)
	Compressors and Limiters
		Attack Artefacts
		Decay Artefacts
		Subtractive VCA Control
	Noise Gates
	Clipping
		Diode Clipping
		Active Clipping With Transistors
		Active Clipping With Opamps
	1. Clipping by Clamping
	2. Negative-Feedback Clipping
	3. Feedforward Clipping
	Noise Generators
	Pinkening Filters
Chapter 25 Power Supplies
	Opamp Supply Rail Voltages
	Designing a ±15 V Supply
	Designing a ±17 V Supply
	Using Variable-Voltage Regulators
	Improving Ripple Performance
	Dual Supplies From a Single Winding
	Power Supplies for Discrete Circuitry
	Larger Power Supplies
	Mutual Shutdown Circuitry
	Very Large Power Supplies
	Microcontroller and Relay Supplies
	+48 V Phantom Power Supplies
Chapter 26 Interfacing With the Digital Domain
	PCB Layout Considerations
	Nominal Levels and ADCs
	Some Typical ADCs
	Interfacing With ADC Inputs
	Some Typical DACs
	Interfacing With DAC Outputs
	Interfacing With Microcontrollers
Appendix
Index