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Index Last Updated - May 2022

banner     Capacitance Multiplier Power Supplies
Curing high inrush current is easy, measurement is harder
A Recent Take on Power Supply Design
Dangerous Power Supplies
Over- And Under-Voltage Protection Techniques
Current Detection and Measurement
Multimeters, Analogue & Digital
Inductor/ Capacitor (LC) Oscillators
Capacitor-Coupled Power Amplifier Behaviour


Quick LinksOverview of Contents ...
Feature ArticlesLamps & Energy Index, Biamping, Counterfeit Parts, PA Systems, Cinema Sound.
AmplificationCharacteristics of Amplifiers, Operating Classes, Clipping, Distortion & Feedback, Dissipation, Protection, Valves.
CablesCoaxial Cables, Impedance, Cable Myths.
Test & MeasurementMeters, Multipliers, Shunts, Weighting Filters, ABX Tests, Squarewave Testing, High Impedance Circuits.
Components & Uses555 Timer, Buffers, Capacitors, Comparators, Fuses, Heatsinks, Relays, Transistors, FETs, Transformers & DC, Variac
Non-AudioInformation about things that have no direct connection to audio.  Relays, Motors, Morse code, Servos, LC oscillators.  More to come as time permits.
Microphones etc.Microphones, Mic Calibration, Audio Transformers, Reverb Tanks, Guitar Measurements.
General InformationAM Radio, Compression, Equalisation, CD Vs SACD, Importing Gear, Morse Code, Sound, Patents, Phono Cartridges.
Electrical SafetynewMaking sure that your working conditions and projects are safe is priority #1.
Beginners' LuckBasics - Electronics, Amplifiers, Bridging, Opamps, Frequency, Amplitude, dB, Pots, Tools, Voltage Dividers.
Design GuidelinesActive Filters, HEXFETs, Amplifiers, Current Sources, Heatsinks, MOSFET Relays, Noise, PSU Design, Sinewaves, Variable Impedance, VCAs, Instrumentation Amps.
Power Supply DesignnewBucking Transformers, Inrush Current, Inverters, Mains Quality, Small PSUs, Transformers, Voltage & Current Regulators, Isolation Transformers, Chargers, Mains Wiring, etc.
Active Crossovers & FiltersActive Vs Passive, Baffle Step, Subtractive Filters, Digital Signal Processing, NTM Crossover, Phase Correction.
Passive Crossover DesignData to help you to provide driver impedance correction, and passive crossover design guides.
Loudspeaker DesignCompliance Scaling, Doppler Distortion, Impedance, Failure Modes, Time Alignment, Subwoofers.
Main IndexESP Home Page

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Feature ArticlesFlag Updated 
Repair Amplifier Troubleshooting and Repair Guide  If it's broken, you may be able to fix it.  This article is designed for those new to repairs Apr 2003
Repair 2 Amp Troubleshooting and Repair Guide - Part 2  Preamps, crossovers and other opamp circuits can cause grief too Jan 2007
Lamps + Energy Lamps & Energy - All material under this heading now has a new home with a separate index May 2015
Biamp Benefits of Bi-Amplification - Not quite magic, but close (Part I) May 2005
Biamp 2 Benefits of Bi-Amplification - Crossovers, tri-amping, etc.  (Part II) May 2005
Cinema Sound Cinema Sound ... Why Isn't It Excellent? - The cinema X-Curve (ISO Bulletin 2969) is used everywhere, but is it right? Mar 2012
Fake Counterfeit (Fake!) Semiconductors - Don't you be caught with fake, below spec transistors when you build a project! Feb 2011
School Education - Customised projects for schools, technical colleges and universities Apr 2003
Amp Development Power Amp Development - Power amps have changed a lot since the late 1940s, and this article covers a multitude of designs since then. Aug 2021
PA Systems Public Address Systems for Music Applications - Something of an exposé on the pitfalls of PA systems. Oct 2009
Manufacture State of Manufacturing - This article should be a mandatory read for all businessmen and politicians, a real wake-up call !  (Nothing has really changed since this was first written.)May 2010
Sustainability The Right To Repair, Projects, DIY & Sustainability - A look at many of the issues that face owners of modern equipment that can't be repaired! April 2020

Amp Sound Amplifier Sound - What causes the perceived differences between amps?  Is it real or imaginary? Apr 2000
Amp Classes Amplifier Classes - What is the difference between Class-A, Class-B and all the others? The characteristics of each are discussed Nov 2017
Amp Classes Amplifier Power - How Much Do You Need?  Probably a lot less than you think. Sep 2019
cap coupling Capacitor Coupled Power Amplifiers - a close examination of just how capacitor coupling works in a power amplifier Jan 2022
Class A Class-A - a discussion of the benefits of Class-A amplifiers Apr 2005
Class G Class-G - One of the lesser known amp classes.  An explanation of how they work Jan 2009
DC Servo DC Servos - Tips, Traps & Applications. Jun 2019
PWM Class-D (PWM) Amplifiers - Theory and design concepts behind these 'new' amplifiers Jun 2005
Clipping Clipping Behaviour - One of the lesser known effects of amplifier clipping, and the damage it can do. Oct 2004
Line Amps Commercial Sound - 70V & 100V 'constant voltage' line public address systems.  Learn the pitfalls before you get caught. Jun 2012
Current Drive Amps Current Drive - Current Drive Power Amplifiers & Effects on Loudspeaker Drivers. Apr 2019
Feedback Distortion & Negative Feedback - A detailed look at the way negative feedback reduces distortion Oct 2006
Guitar Amps Guitar Amplifiers - Often there is little point repairing, and a replacement power amp should be considered.  This explains why. Feb 2011
Guitar Speakers Guitar Speakers - A detailed examination of the things that go towards 'the sound' of guitar speakers. Sep 2018
Boosted IC Amps IC Power Amplifiers - Getting more power by adding booster transistors. Jan 2019
Intermodulation Intermodulation Distortion - Interesting finding, symmetrical Vs. asymmetrical.  Where did the difference frequency go? Sep 2012
Intermodulation Intermodulation Distortion - How it's measured, and what it does to the sound.  A description of the common IMD tests and how it's created. Feb 2019
Guitar Musical Instrument Amplifiers - Guitar, Bass and Keyboard  Feb 2001
Protection Short Circuit Protection - Testing amplifiers to the limits ‡ Aug 2000
Soft Clip Soft Clipping - Is adding a soft-clip circuit worth the effort? Apr 2006
Speed The Need For Speed - Very high speed opamps from Texas Instruments Aug 2001
Phase Phase Angle Vs. Transistor Dissipation - A simplified approach to understanding Safe Operating Area Mar 2005
SIM Sound Impairment Monitor - Is This The Answer? - A new method to monitor distortion in real time Sep 2000
SOA Transistor Safe Operating Area - What is SOA, and how does it affect amplifier designs Aug 2003
Valve Valves & Amplifiers - A separate section that includes information about valves, myths, etc. Jan 2010

Cable Comparison Audio Interconnect Comparisons - Using a null test methodology, this demonstrates the (virtually non-existent) differences between cables. Oct 2003
Coax Cable Coaxial Cables - An introduction to coaxial (coax) cables, and where (and why) they are used Jul 2016
Cable Z Cable Impedance - Characteristic impedance, high capacitance designs and amp stability Oct 2003
Cable The Truth About Cables, Interconnects and Audio in General - A 'must read' article Sep 2002
White Paper More Truth About Cables - A white paper discussing speaker cables and interconnects *‡ Jul 2001

Test & MeasurementFlagUpdated
A-B A-B Switch Box for Amplifier Comparisons - Something to offend everyone, or a great tool? ‡ Aug 2000
ABX ABX Comparator - A true ABX system that does not need a PC or microcontroller ‡ Aug 2002
Attenuators Attenuators - How to design meter (and oscilloscope) attenuators.  Definitely an article for 'hard-core' enthusiasts  Dec 2021
A-weighting A-Weighting And Sound Measurements ... How the indiscriminate use of A-weighting causes grief  Sep 2012
current Current Detection and Measurement - A look at the various techniques used for current monitoring (measurement) and detection. new Mar 2022
High Impedance High Impedance Circuits - a collection of circuits for piezo sensors, test & measurement applications Mar 2020
inrush test Inrush Testing - Testing for worst-case inrush current isn't easy, but this mains switching unit allows repeatable results for transformer and electronic loads. new May 2022
Meters Meters, Multipliers & Shunts - How to use analogue and digital panel meters May 2006
Multimeters Multimeters.  Analogue Vs. Digital with a discussion of the advantages/ disadvantages of each.  Includes insulation testers, VTVMs, FET meters, etc. Feb 2022
Oscilloscopes Oscilloscopes ... How They Work And Their Usage Mar 2017
Squarewave Testing Squarewave Testing - How to interpret the changes made to a squarewave by amplifiers, tone controls and filters Feb 2015

Components & UsesFlagUpdated 
555 The 555 Timer - How to use it, and some example circuits May 2015
BJT BJT Parameters - An examination of fundamental bipolar transistor parameters and function.  (Now includes switching.) Feb 2020
Parts Buying Parts - A general look at the parts you need for electronics hobby work. Oct 2007
Caps Capacitors - What are the influences that determine the so-called 'sound' of capacitors.  Covers dielectrics, dissipation factor, etc. Oct 2005
Current Comparators - The unsung heroes of electronics.  An examination of their performance and usage in circuitry. Aug 2016
Compound vs. Darlington Compound vs. Darlington - An explanation of the differences between Compound (Sziklai) and Darlington pairs. Jan 2011
DC and Transformers DC Offset and Transformers - Many people have found that toroidal transformers growl at times.  This explains why, & how to fix it. Mar 2008
FETs and MOSFETS FETs (& MOSFETs) - Applications, Advantages and Disadvantages Sep 2017
Fusing Fusing - Circuit protection, how to select the right circuit protection device to prevent serious damage ‡ Sep 2009
Equalisation Follow The Leader - Voltage Followers & Buffers, the techniques and different topologies are discussed, with the advantages and disadvantages of each explained Jul 2016
Heatsink Heatsink - Build Your Own? - Yes, it can be done.  If you have the tools, you can make a heatsink as big as you'll ever want. Feb 2006
lm358 LM358 and LM324 performance improvements - How to (almost) eliminate distortion with these versatile, low-cost opamps. Sep 2021
Variac Transformers ... The Variac - One of the most useful but misunderstood pieces of workshop equipment. Feb 2009

Non-Audio InformationFlagUpdated
Arc Prevention Contact Arc Mitigation & Prevention.  How to extend the contact life of relays and contactors Sep 2020
Hybrid Relays Hybrid Relays - Hybrid Relays using MOSFETs, TRIACs and SCRs.  Improved performance & reliability for difficult loads Aug 2020
LC osc Inductor/ Capacitor (LC) Oscillators.  These began the era of radio ('wireless') as we know it.  These are not directly related to audio, but are important building-blocks.Feb 2022
Morse Code Morse Code - The birth of electronic messaging, and there's more to it than you might think. Nov 2016
Motors Electric Motors - Types, Uses And Powering.  All common motor types are covered, but this is intended as a 'starter guide' Jul 2020
Relays Relays (Part 1) - What they are, what they do, and how to get the best results from them Dec 2014
Relays Relays (Part 2) - Getting the best results from relay contacts & minimising arcing Jan 2015
Servos Servos, remote control, electronic speed controls and tachometers.  Includes sample schematics and photos of typical equipment. Jan 2018
Servos Solid State Relays, Types & Usage.  MOSFET, IGBT, TRIAC & SCR types, with schematics and explanations of typical designs. Nov 2020

Microphones & Audio TransformersFlagUpdated 
feedback Acoustic Feedback In PA Systems, With Special Reference To Frequency Shifting Feb 2017
Mics Electret Microphones - Powering & Uses Feb 2017
Guitar Guitar Voltages - How much level should you expect from electric guitar pickups? Mar 2021
Mics Microphones - An introduction to the different types, polar response and behaviour of microphones Jan 2006
Mics2 Microphones Part 2 - Measurement microphones, sound level meters and calibrators Nov 2016
Mics2 Microphone Splitters - How to send the output from a single mic to multiple destinations Dec 2016
70/100V Lines PA Transformers - 70V & 100V 'constant voltage' line public address systems.  Learn the pitfalls before you get caught.  These apply whenever any amp is connected to a transformer!Jun 2012
70/100V Lines Phantom Power - What It Is And How It Works.  Phantom power (aka P48) isn't really as simple as it seems at first.  This article is an in-depth look at the schemes used and how it fits together.Oct 2021
Reverb Reverberation - The care and feeding of spring reverb tanks Sep 2009
Line Level Xfmrs Transformers for 'Line Level' Audio - Extremely versatile and with many features unobtainable with active circuits, but there are traps! Sep 2014

General InformationFlagUpdated 
AM AM Radio - Approaches to high fidelity AM broadcast band reception ‡ Feb 2006
AM Amplitude Modulation - How to generate AM waveforms in a simulator to test detector performance. Aug 2016
Analogue vs Digital Analogue vs Digital - Does 'Digital' Really Exist? The question isn't as silly as it sounds at first! Apr 2017
CD etc CD, SACD and DVD-A - A Comparison of the formats in a discussion between Niklas Ladberg and Ing. Ohman (very interesting) ‡ Aug 2002
Compression Compression In Audio - Ever wondered why some music sounds flat and lifeless, even though it's loud? Dec 2001
Earthing Earthing Your Hi-Fi - Tricks and Techniques - How to eliminate hum without affecting safety Dec 1999
Electrocution Electrocution - How to avoid being electrocuted, what to do if the worst happens Apr 2007
Equalisation Equalisation - Equalisers, The Various Types And How They Work.  From 'Tone Controls' to Parametric EQ Feb 2021
50-60Hz Importing Equipment From Overseas ... Effects of Voltage & Frequency on Electronic Equipment (50/60Hz can make a big difference !) Feb 2010
Illusion Is Sound an Illusion - An interesting discussion about our perception of sound ‡ Sep 2009
Impedance Impedance - What does it really mean?  A general discussion on impedance, damping, etc. Jan 2005
Muting Muting Circuits - Looking at the various options available for muting an audio signal Oct 2015
Myths Myths in Audio - A Look at some of the more entrenched myths, as well as some that are just too silly for words. Jul 2012
Patents Patents - A look at the patent system, and how (or if) it affects the DIY fraternity.  ‡ May 2010
Phono Cartridge Phono Cartridge Loading - A detailed examination of the phono cartridge, and how loading affects response Jan 2012
Tweeters Why Do Tweeters Blow? - The real reason that tweeters (and other drivers) are destroyed by distortion Jun 2012
What Is-1 What is Hi-Fi - A contributed article on some of the subtle aspects of Hi-Fi ‡ May 2001
What Is-2 What is Hi-Fi (Part II) - Continuation of 'What is Hi-Fi' explaining the idea of accuracy (amongst other things) Mar 2004
Yellow Glue Yellow Glue - The Enemy Of Electronics - This is a problem mainly seen by service technicians, but it may still affect products you buy Nov 2019

Electrical Safety - Make sure that you and your loved ones are protected from harm.FlagUpdated
dangerous PSUs Dangerous Power Supplies - Plug-Pack ('Wall-Wart') power supplies are common and low cost, but don't get caught by un-certified products, some of which are seriously dangerous. newApr 2022
Isolation Transformers Isolation Transformers - is an isolating transformer on the test bench a good safety measure or a death trap? Dec 2016
Mains Safety Mains Safety - Wiring Standards, Insulation, Class I, Class II and Important Information.  Wiring of mains is poorly understood by many, and applicable standards vary worldwide. Mar 2019
Supply Power Supply Wiring - There are a lot of considerations for the wiring of a PSU - read about it here Jun 2003

Beginners' Luck - The beginners' Guide to ...FlagUpdated
Lenard Electronics Basics - The Lenard Audio site has an education section that is recommended for those just starting out
Beginner 1 Electronics - Part 1   If you are a beginner, read these two articles first.  Covers passive components - resistors, capacitors and inductors Mar 2001
Beginner 2 Electronics - Part 2  The resistor 'E' series (e.g. E12, E24, etc), Zener Diodes Mar 2004
Basics Amplifier Basics - (Introduction) How Amps Work - How amplifiers do what they do, six part series Apr 2005
Efficiency Amplifier Efficiency - Power Loss, DC voltages and current explained  Jan 2000
Bridging Bridging - How the 'Trimode' bridging system works in car power amplifiers Oct 2002
Etiquette Bulletin Boards - A guide to etiquette when posting at your favourite forum ‡Grin Apr 2001
Opamps 1 Designing With Opamps I - What they are, what they do, and how they do it May 2000
Opamps 2 Designing With Opamps II - Audio applications, filters, crossovers, etc. May 2000
Opamps 3 Designing With Opamps III - More Filters, Specifications, Comparators, etc. May 2006
dB Frequency, Amplitude and dB - An explanation of the terms, what they mean, and how they are applied Dec 2006
logic Logic - The general principles of basic logic.  Logic families, gates, flip flops and counters. Jan 2020
Mixing Mixing - Active Vs. Passive - The basic principles of mixing two or more signals, as used in simple applications through to multi-channel mixers. Oct 2010
Pots Potentiometers - what they are and how to use them in practical circuits. Jan 2003
Power Power - An explanation of the derivation of PMPO in amplifiers.  Light reading, reallyGrin Jun 2000
Tools Tools - The basics of the mechanical aspects of your hobby ‡ Mar 2001
Dividers Voltage Dividers & Attenuators - A short article describing how to design these essential circuits Dec 2002

Design GuidelinesFlagUpdated
Active Filters Active Filters - Active filter design guide ... topologies, component selection, slope (dB/octave), transient response, etc. Jan 2014
State-Variable Filters Active Filters, State-Variable - The state-variable active filter is one of the most versatile designs known.  Find out what they can do. Dec 2012
Gyrator Avtive Filters Active Filters Using Gyrators - Some of the simplest and most complex filters used are based on gyrators.  The range is huge, but good results can be obtained with simple designs Aug 2021
Design Amplifier Design - ESP's contribution to the everlasting debate Jun 2001
HEXFETs Amplifier Design With HEXFETs - Getting good performance from vertical MOSFETs is possible (Updated) Mar 2014
Balanced Balanced Driver (Part 1) - with Floating Output.  An in depth discussion of the design process ‡ Apr 2002
Balanced 2 Balanced Interfaces (Part 2) - Essential reading for anyone designing equipment using balanced interconnects ‡ Jan 2010
Balanced 3 Balanced Interfaces (Part 3) - Inputs & Outputs (The things no-one tells you) Sep 2017
Balanced 4 Balanced Interfaces (Part 4) - The Confounding Case Of The Differential Amplifier Balanced Input Stage (It's much better than some people claim) Sep 2021
Cfb Vs Vfb Current Feedback Vs. Voltage Feedback - The two are very different, and it's worthwhile knowing how CFB amps and opamps work, and why you may need CFB rather than VFB. Aug 2021
Current Current Sources, Sinks & Mirrors - A discussion on these much misunderstood circuits. Apr 2007
DC and Transformers DC Offset On AC Mains and Transformers - Many people have found that toroidal transformers growl at times.  This explains why, & how to fix it. Mar 2008
Designing With JFETs Designing circuits with JFETs (junction field-effect transistors) can be challenging - Most of the JFETs you can get have a wide parameter spread, making them difficult to work with. Apr 2021
Heatsink Heatsinks - An article on heatsink selection, transistor mounting and thermal transfer principles Feb 2021
Heatsink+Amplifiers How much heatsink do I need for my amplifier? How long is a piece of string? - A discussion on sizing the heatsink for your amplifier May 2015
Instrumentation Amplifiers INAs (Instrumentation Amplifiers) vs Opamps.  A look at some common INAs, how they work, and how to use them.  Comparisons between INAs and common opamp circuits are shown.Aug 2017
MOSFET Relay MOSFET Relays - Very different, but extremely useful for high power amps that will destroy any normal relay. Dec 2019
Negative Impedance Negative Impedance - What It Is, What It Does, And How It Can Be Useful May 2017
Noise Noise in Audio Amplifiers - An explanation of noise figures, and how circuit noise is calculated Jan 2000
Pre-Opamp Opamp Alternatives - A sample of the circuits that were in common use before opamps 'took over' Apr 2014
Supply Power Supply Design - How to design linear power supplies - transformers, rectifiers and filters Dec 2007
Supply Sinewave Oscillators/ Generators - An examination of different sinewave generation techniques. Apr 2010
Matching Transistor Matching Tests - Matching Bipolar or MOSFET transistors for critical amplifier applications Dec 2001
Variable Variable Impedance Amplifiers - How you can control the output impedance of a power amp Apr 2000
VCAs Voltage controlled Amplifiers/ Attenuators - An investigation into VCA techniques, including JFETs, LED/LDR modules and 'true' VCAs Dec 2012

Power Supply DesignFlagUpdated
Supply Bench Power Supplies - Buy Or Build?  One of the most challenging DIY builds is a good, reliable bench power supply (includes examples, but is not a construction article!)Nov 2019
Supply Bleeder Resistors, and using Active bleeders to discharge PSU capacitors when power is removed. Oct 2020
Supply Bucking Transformers - Here is a bit more info than you'll find elsewhere - how to do it properly May 2010
cap mult Capacitance Multiplier Power Supplies - The name is wrong, but they are still useful.  The design process, and a close look at the filter network. newMay 2022
DC and Transformers DC Offset On AC Mains and Transformers - Many people have found that toroidal transformers growl at times.  This explains why, & how to fix it. Mar 2008
Regulators 2 Discrete Voltage Regulators - Used when you cannot use an IC regulator because the voltage or current is too high Dec 2021
E-Fuse Electronic Fuses - A collection of useful ideas with example circuits.  These aren't always as hard as you might think Feb 2020
Inrush Inrush Current - What it is, what it can do, and how to prevent it from causing problems Oct 2010
Inrush tests Inrush Current Tester - Minimising inrush current is easy enough, but it's surprisingly difficult to measure it.  This tester will turn on the mains at zero crossing or at the peak of the AC cyclenewMay 2022
Isolation Transformers Isolation Transformers - is an isolating transformer on the test bench a good safety measure or a death trap? Dec 2016
Inverters Inverters - Squarewave, modified squarewave, modified sinewave, pure sinewave - What are the differences, and should you really care? Mar 2014
LDO Regulators LDO (Low Dropout) Voltage Regulators - A short primer on these sometimes difficult devices Mar 2017
Lithium Charging Lithium Charging - Lithium Cell Charging & Battery Management.  Not as simple as it seems. Feb 2017
Mains Quality Mains Power Quality - Does it matter if the mains is distorted, and is an expensive 'regenerator' or other system worth the price? Aug 2014
Mains Safety Mains Safety - Wiring Standards, Insulation, Class I, Class II and Important Information.  Wiring of mains is poorly understood by many, and applicable standards vary worldwide. Mar 2019
overvoltage Over- And Under-Voltage Protection Techniques For Sensitive Electronics.  How to protect expensive electronics from damage caused by a failed power supply or other major failure. newApr 2022
Supply Power Supply Design - How to design linear power supplies - transformers, rectifiers and filters Dec 2007
Supply Power Supply Design Part II - the design of linear power supplies - transformers, rectifiers and filters and SMPS comparisonsnew Apr 2022
Preregulators Power Supply Pre-Regulator Techniques - A look at the various types of bench power supply pre-regulators Feb 2020
Supply Power Supply Simulations - not quite as simple as they first appear. Sep 2019
Snubbers Power Supply Snubbers - Are They Necessary And Why Might I Need One? Jan 2019
Supply Power Supply Wiring - There are a lot of considerations for the wiring of a PSU - read about it here Jun 2003
Recrifiers Rectifiers.  Half wave, full wave, bridge, voltage doublers & multipliers and multi-phase rectifiers explained. Feb 2018
Reverse polarity Reverse Polarity Protection.  Using diodes, MOSFETs or bipolar transistors to protect circuitry from damage if the supply polarity is reversed (AN013). Jan 2017
Transformer 3 Small Power Supplies (Part I).  Design of small PSUs - includes information that might save your life ! May 2008
Transformer 3 Small Power Supplies (Part II).  Regulated Power Supplies, Transient Response & Noise April 2018
Soft Start Soft Start Circuits - a follow-on article to augment the 'Inrush Current' article listed above Dec 2017
Supply Switchmode Power Supply Primer - A discussion covering the different types of SMPS, and how they work Oct 2015
Transformer 1 Transformers, Part 1 - The basics of transformers, what they do, and how they do it May 2001
Transformer 2 Transformers, Part 2 - The details of magnetic circuits, windings, core types and losses.  Now includes current transformers Oct 2012
Transformer 3 Transformers, Part 3 - Designing and analysing transformers - not at all for the faint-hearted, but all very useful information Jan 2006
Transformer 4 Transformers, Part 4 - Further information on transformer usage, including captured waveforms and worked examples Jan 2006
Regulators Voltage & Current Regulators - The basics of both voltage and current regulators, and how (and where) to use them Jul 2013

Active Crossovers, Filters and Signal ProcessingFlagUpdated
Active Vs. Passive Active Vs. Passive Crossovers - An explanation for the profound audible differencesJan 2004
Baffle Baffle Step Compensation - What it is and why we need to compensate for itDec 2001
Derived Derived (Subtractive) Crossovers - An examination of these networks, and why they are unsuitable for serious use Sep 2005
DSP Digital Signal Processing (DSP) - What DSPs can (and cannot) do for your system Dec 2006
NTM NTM™ Crossovers - This is a topic that has virtually zero technical information on the Net ... until now. Sep 2005
PLLXO Passive Line Level Crossovers (PLLXO).  Useful Or Not? Apr 2020
Phase Phase Correction - Myth or Magic? - Do all-pass filters really work to correct loudspeaker phase anomalies? May 2007
Phase Using Phase Shift Networks To Achieve Time Delay For Time Alignment. Nov 2020

Passive Crossover Network DesignFlagUpdated
6dB Serial 6dB/ Octave Serial Crossover Networks - The simplest of all, but only for low to moderate powerMay 2020
Serial Impedance Compensation For Passive Crossovers - How to make any driver appear resistive to the crossover network May 2020
Passive Passive Crossovers - The Design of High Quality Passive Crossover Networks Nov 2001
Serial Serial vs. Parallel Crossover Networks - Are there any real differences? Aug 2003
Serial Passive Crossover Design Tables - Make your life a little easier with this handy guide to crossover design. May 2020
L-Pad Loudspeaker L-Pad Calculations.  An online calculator and formulae for calculating the values for L-Pads. Aug 2018

Loudspeaker DesignFlagUpdated
Compliance Compliance Scaling - Fitting just about any driver to just about any alignment Jun 2005
Current Drive Current Drive - Current Drive Power Amplifiers & Effects on Loudspeaker Drivers. Apr 2019
Doppler Doppler Distortion in Loudspeakers - Is the effect real or imaginary when applied to loudspeakers?  The results may surprise you Aug 2004
enclosures Enclosure Design Guidelines - Some tips, tricks and techniques to help you design an optimum loudspeaker enclosure. Sep 2019
Guitar Speakers Guitar Speakers - A detailed examination of the things that go towards 'the sound' of guitar speakers. Sep 2018
Impedance Impedance - Effects Of Source Impedance on Loudspeaker DriversJul 2001
Transform The Linkwitz Transform Circuit - What it is, what it does and how it does it ‡ Sep 2002
Loudspeaker Failures Loudspeaker Failure Modes - Why do loudspeakers fail? What can be done to prevent failures? Not what you expect! ‡ Jun 2012
Pwr vs. Eff Loudspeaker Power vs. Efficiency - There's more to this than meets the eye Dec 2006
Speakers 1 Loudspeakers (Part I) - see the production of my latest triamped speaker boxes unfold Jul 2001
Speakers 2 Loudspeakers (Part II) - The electronics that drive the 3-way system are described Nov 2001
Phase Phase, Time and Distortion in Loudspeakers - Is 'Time Alignment' worth the effort? Jul 2002
Pikku Pikku 9 - Simple Network Lowers f3 - A useful approach for obtaining better bass from a very small loudspeaker ‡ Jul 2006
Subs 1 Satellites & Subwoofers - Description of the little known QB5 loudspeaker alignment.  Maximum SPL from 2-way bookshelf speakers. ‡ Aug 2004
SSL Small Satellite Loudspeaker - Using techniques described in various articles, this project should have wide appeal for home theatre ‡ May 2007
Subs 2 Subwoofer Conundrum - Some tips and hints on subwoofer selection, efficiency and placement Mar 2004
TSP Thiele Small Parameters - Determining the Thiele/Small parameters for a loudspeaker driver Jan 2006
Box Stuffing Volume Filling a Reflex Box - It is generally thought that vented boxes should not be filled, but this isn't necessarily the case ‡ Feb 2007
Waveguides Practical DIY Waveguides - Waveguide definition, calculation and construction ‡ Dec 2006

Explanation of Symbols ...

NewNew article.  Less than 3 months old (typically).
REDDates in the update column indicate a new or updated (within three months) article.  Usually accompanied by Update
GrinIndicates an article that may include humour - caution is advised
Contributed article (see copyright notice on article page)

Main IndexMain Index
Please refer to Copyright information in the individual articles.  All articles are Copyright © 1998 - 2022 Rod Elliott, unless otherwise stated.  The material presented on the ESP website is not public domain.  All material is Copyright!

Although it goes without saying (but I will say it anyway grin) the contributed articles and projects from all over the world have added considerably to the overall value and range of topics covered in these pages, and on behalf of all the readers of The Audio Pages, I thank you for you efforts.  Writing a clear and descriptive technical article is not an easy task, but your perseverance is acknowledged, and I am grateful that you have taken the time to share your knowledge.

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