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Page Last Updated - 29 December 2012


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Feature Articles Updated

Lamps + EnergyLamps & Energy - All material under this heading now has a new home with a separate index02 Dec 11
 
BiampBenefits of Bi-Amplification - Not quite magic, but close (Part I)02 May 05
Biamp 2Benefits of Bi-Amplification - Crossovers, tri-amping, etc. (Part II)02 May 05
FakeCounterfeit (Fake!) Semiconductors - Don't you be caught with fake, below spec transistors when you build a project!13 Feb 11
SchoolEducation - Customised projects for schools, technical colleges and universities30 Apr 03
ManufactureThe State of Manufacturing - This article should be a mandatory read for all businessmen and politicians, a real wake-up call !16 May 10
PA SystemsPublic Address Systems for Music Applications - Something of an exposé on the pitfalls of PA systems   03 Oct 09
Cinema SoundCinema Sound ... Why Isn't It Excellent? - The cinema X-Curve (ISO Bulletin 2969) is used everywhere, but is it right?   28 Mar 12

Amplification

Amp SoundAmplifier Sound - What causes the perceived differences between amps?  Is it real or imaginary?09 Apr 00
Class AClass- A - a discussion of the benefits of Class-A amplifiers02 Apr 05
Class GClass- G - One of the lesser known amp classes. An explanation of how they work06 Jan 09
ClippingClipping Behaviour - One of the lesser known effects of amplifier clipping, and the damage it can do.15 Oct 04
70/100V Line AmpsCommercial Sound - 70V & 100V 'constant voltage' line public address systems. Learn the pitfalls before you get caught. 20 Jun 12
FeedbackDistortion & Negative Feedback - A detailed look at the way negative feedback reduces distortion17 Oct 06
Guitar AmpsGuitar Amplifiers - Often there is little point repairing, and a replacement power amp should be considered. Here is why.14 Feb 11
IntermodulationIntermodulation Distortion - Interesting finding, symmetrical Vs. asymmetrical. Where did the difference frequency go?23 Sep 12
GuitarMusical Instrument Amplifiers - Guitar, Bass and Keyboard 04 Feb 01
ReverbReverberation - The care and feeding of spring reverb tanks    17 Sep 09
ProtectionShort Circuit Protection - Testing amplifiers to the limits ‡22 Aug 00
Soft ClipSoft Clipping - Is adding a soft-clip circuit worth the effort?15 Apr 06
SpeedThe Need For Speed - Very high speed opamps from Texas Instruments17 Aug 01
PhasePhase Angle Vs. Transistor Dissipation - A simplified approach to understanding Safe Operating Area19 Mar 05
PWMPWM (Class-D) Amplifiers - Theory and design concepts behind these 'new' amplifiers25 Jun 05
SIMSound Impairment Monitor - Is This The Answer? - A new method to monitor distortion in real time23 Sep 00
SOATransistor Safe Operating Area - What is SOA, and how does it affect amplifier designs14 Aug 03
ValveValves & Amplifiers - A new section that includes information about valves, myths, etc.17 Jan 10

Cables

Cable The Truth About Cables, Interconnects and Audio in General - A "must read" article 20 Sep 02
White Paper More Truth About Cables - A white paper discussing speaker cables and interconnects *‡ 22 Jul 01
Cable Z Cable Impedance - Characteristic impedance, high capacitance designs and amp stability 17 Oct 03

General Information

A-weightingA-Weighting And Sound Measurements ... How the indiscriminate use of A-weighting causes grief   23 Sep 12
A-BA-B Switch Box for Amplifier Comparisons - Something to offend everyone, or a great tool? ‡15 Aug 00
ABXABX Comparator - A true ABX system that does not need a PC or microcontroller ‡11 Aug 02
AMAM Radio - Approaches to high fidelity AM broadcast band reception ‡18 Feb 06
PartsBuying Parts - A general look at the parts you need for electronics hobby work.16 Oct 07
CapsCapacitors - What are the influences that determine the so-called 'sound' of capacitors. Covers dielectrics, dissipation factor, etc.25 Oct 05
CD etcCD, SACD and DVD-A -A Comparison of the formats in a discussion between Niklas Ladberg and Ing. Ohman (very interesting)28 Aug 02
CompressionCompression In Audio - Ever wondered why some music sounds flat and lifeless, even though it's loud?21 Dec 01
DC and TransformersDC Offset and Transformers - Many people have found that toroidal transformers growl at times. This explains why, & how to fix it.09 Mar 08
Compound vs. DarlingtonCompound vs. Darlington - An explanation of the differences between Compound (Sziklai) and Darlington pairs.06 Jan 11
EarthingEarthing Your Hi-Fi - Tricks and Techniques - How to eliminate hum without affecting safety30 Dec 99
ElectrocutionElectrocution - How to avoid being electrocuted, what to do if the worst happens28 Apr 07
FusingFusing - Circuit protection, how to select the right circuit protection device to prevent serious damage ‡   17 Sep 09
HeatsinkHeatsink - 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.11 Feb 06
50-60HzImporting Equipment From Overseas ... Effects of Voltage & Frequency on Electronic Equipment (50/60Hz can make a big difference !)   05 Feb 10
IllusionIs Sound an Illusion - An interesting discussion about our perception of sound ‡   27 Sep 09
ImpedanceImpedance - What does it really mean?  A general discussion on impedance, damping, etc.24 Jan 05
MicsMicrophones - An introduction to the different types, polar response and behaviour of microphones12 Jan 06
MythsMyths in Audio - A Look at some of the more entrenched myths, as well as some that are just too silly for words. 21 Jul 12
PatentsPatents - A look at the patent system, and how (or if) it affects the DIY fraternity.   ‡15 May 10
Phono CartridgePhono Cartridge Loading - A detailed examination of the phono cartridge, and how loading affects response19 Jan 12
Transformers - the VariacTransformers ... The Variac - One of the most useful but misunderstood pieces of workshop equipment.20 Feb 09
TweetersWhy Do Tweeters Blow? - The real reason that tweeters (and other drivers) are destroyed by distortion 09 Jun 12
What Is-1What is Hi-Fi - A contributed article on some of the subtle aspects of Hi-Fi ‡05 May 01
What Is-2What is Hi-Fi (Part II) - Continuation of 'What is Hi-Fi' explaining the idea of accuracy (amongst other things)29 Mar 04

Beginners' Luck - The beginners' Guide to ...

LenardElectronics Basics - The Lenard Audio site has an education section that is highly recommended for those just starting out
BasicsAmplifier Basics - How Amps Work - How amplifiers do what they do06 Apr 05
EfficiencyAmplifier Efficiency - Power Loss, DC voltages and current explained 29 Jan 00
RepairAmplifier Troubleshooting and Repair Guide  If it's broken, you may be able to fix it. This article is designed for those new to repairs27 Apr 03
Repair 2Amp Troubleshooting and Repair Guide - Part 2  Preamps, crossovers and other opamp circuits can cause grief too06 Jan 07
BridgingBridging - How the "Trimode" bridging system works in car power amplifiers20 Oct 02
EtiquetteBulletin Boards - A guide to etiquette when posting at your favourite forum ‡ Grin09 Apr 01
Opamps 1Designing With Opamps I - What they are, what they do, and how they do it03 May 00
Opamps 2Designing With Opamps II - Audio applications, filters, crossovers, etc.08 May 00
Opamps 3Designing With Opamps III - More Filters, Specifications, Comparators, etc.11 May 06
Beginner 1Electronics - Part 1  Passive components - resistors, capacitors and inductors explained 13 Mar 01
Beginner 2Electronics - Part 2  The resistor 'E' series (e.g. E12, E24, etc), Zener Diodes05 Mar 04
dBFrequency, Amplitude and dB - An explanation of the terms, what they mean, and how they are applied02 Dec 06
MetersMeters, Multipliers & Shunts - How to use analogue and digital panel meters06 May 06
MixingMixing - Active Vs. Passive - The basic principles of mixing two or more signals, as used in simple applications through to multi-channel mixers.05 Oct 10
PotsPotentiometers.  - what they are and how to use them in practical circuits.22 Jan 03
PowerPower - An explanation of the derivation of PMPO in amplifiers.  Light reading, really Grin19 Jun 00
ToolsTools - The basics of the mechanical aspects of your hobby ‡21 Mar 01
DividersVoltage Dividers & Attenuators - A short article describing how to design these essential circuits21 Dec 02

Design Guidelines

Active FiltersActive Filters - Active filter design guide ... topologies, component selection, slope (dB/octave), transient response, etc.29 Aug 09
State-Variable FiltersActive Filters, State-Variable - The state-variable active filter is one of the most versatile designs known. Find out what they can do.10 Dec 12
DesignAmplifier Design - ESP's contribution to the everlasting debate09 Jun 01
HEXFETsAmplifier Design With HEXFETs - Getting good performance from vertical MOSFETs is possible (Updated)13 Mar 06
BalancedBalanced Driver with Floating Output - An in depth discussion of the design process ‡14 Apr 02
Balanced 2Balanced Interfaces - Essential reading for anyone designing equipment using balanced interconnects ‡ 19 Jan 10
CurrentCurrent Sources, Sinks & Mirrors - A discussion on these much misunderstood circuits.28 Apr 07
HeatsinkHeatsinks - An article on heatsink selection, transistor mounting and thermal transfer principles17 Sep 03
MOSFET RelayMOSFET Relays - Very different, but extremely useful for high power amps that will destroy any normal relay 09 Jun 12
NoiseNoise in Audio Amplifiers - An explanation of noise figures, and how circuit noise is calculated29 Jan 00
Pre-OpampOpamp Alternatives - A sample of the circuits that were in common use before opamps 'took over'28 Apr 05
SupplyPower Supply Design - How to design linear power supplies - transformers, rectifiers and filters03 Dec 07
SupplySinewave Generators - An examination of different sinewave generation techniques.16 Apr 10
MatchingTransistor Matching Tests - Matching Bipolars or MOSFETs for critical amplifier applications08 Dec 01
VariableVariable Impedance Amplifiers - How you can control the output impedance of a power amp22 Apr 00
VCAsVoltage controlled Amplifiers/ Attenuators - An investigation into VCA techniques, including JFETs, LED/LDR modules and 'true' VCAs 29 Dec 12

Power Supplies

SupplyBucking Transformers  Here is a bit more info than you'll find elsewhere - how to do it properly23 May 10
InrushInrush Current  What it is, what it can do, and how to prevent it from causing problems25 Oct 10
SupplyPower Supply Wiring  There are a lot of considerations for the wiring of a PSU - read about it here07 Jun 03
Transformer 1Transformers - Part 1  The basics of transformers, what they do, and how they do it.05 May 01
Transformer 2Transformers - Part 2  The details of magnetic circuits, windings, core types and losses. Now includes current transformers   20 Oct 12
Transformer 3Transformers - Part 3  Designing and analysing transformers - not at all for the faint-hearted, but all very useful information.16 Jan 06
Transformer 3Small Power Supplies  Design of small PSUs - includes information that might save your life !12 May 08

Crossovers, Filters and Signal Processing

Active Vs. PassiveActive Vs. Passive Crossovers - An explanation for the profound audible differences11 Jan 04
BaffleBaffle Step Compensation - What it is and why we need to compensate for it08 Dec 01
DerivedDerived (Subtractive) Crossovers - An examination of these networks, and why they are unsuitable for serious use21 Sep 05
DSPDigital Signal Processing (DSP) - What DSPs can - and cannot - do for your system09 Dec 06
NTMNTM™ Crossovers - This is a topic that has virtually zero technical information on the Net ... until now.15 Sep 05
PassivePassive Crossovers - The Design of High Quality Passive Crossover Networks05 Nov 01
PhasePhase Correction - Myth or Magic? - Do all-pass filters really work to correct loudspeaker phase anomalies?27 May 07
SerialSerial vs. Parallel Crossover Networks - Are there any real differences?14 Aug 03

Loudspeaker Design

ComplianceCompliance Scaling - Fitting just about any driver to just about any alignment30 Jun 05
DopplerDoppler Distortion in Loudspeakers - Is the effect real or imaginary when applied to loudspeakers?  The results may surprise you23 Aug 04
ImpedanceImpedance - Effects Of Source Impedance on Loudspeaker Drivers22 Jul 01
TransformThe Linkwitz Transform Circuit - What it is, what it does and how it does it ‡16 Sep 02
Loudspeaker FailuresLoudspeaker Failure Modes - Why do loudspeakers fail? What can be done to prevent failures? Not what you expect! ‡ 02 Jun 12
Pwr vs. EffLoudspeaker Power vs. Efficiency - There's more to this than meets the eye16 Dec 06
Speakers 1Loudspeakers (Part I) - see the production of my latest triamped speaker boxes unfold14 Jul 01
Speakers 2Loudspeakers (Part II) - The electronics that drive the 3-way system are described18 Nov 01
PhasePhase, Time and Distortion in Loudspeakers - Is "Time Alignment" worth the effort?30 Jul 02
PikkuPikku 9 - Simple Network Lowers f3 - A useful approach for obtaining better bass from a very small loudspeaker ‡23 Jul 06
Subs 1Satellites & Subwoofers - Description of the little known QB5 loudspeaker alignment.  Maximum SPL from 2-way bookshelf speakers. ‡28 Aug 04
SSLSmall Satellite Loudspeaker - Using techniques described in various articles, this project should have wide appeal for home theatre ‡ 27 May 07
Subs 2Subwoofer Conundrum - Some tips and hints on subwoofer selection, efficiency and placement12 Mar 04
TSPThiele Small Parameters - Determining the Thiele/Small parameters for a loudspeaker driver12 Jan 06
Box StuffingVolume Filling a Reflex Box - It is generally thought that vented boxes should not be filled, but this isn't necessarily the case ‡05 Feb 07
WaveguidesPractical DIY Waveguides - Waveguide definition, calculation and construction ‡01 Dec 06

Explanation of Symbols ...

NewThe article is new - that must come as a surprise GRIN  Less than 2 months old (typically).
REDDates in the update column indicate a new or updated (within 2 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 ... 2012 Rod Elliott, unless otherwise stated.
Although it goes without saying (but I will say it anyway :-) 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.

May the flow of input continue - for anyone who would like to contribute, please do not hesitate to contact me.


Upcoming Articles

At any given time, there are usually articles in production either by myself or contributors. It is no longer possible (or sensible) to leave hints as to what may or may not be coming, since it is so easy to get sidetracked by something new that comes along. Feel free to offer suggestions, or offer your own contribution.

Total Visitors since Jan 2001 - 

Last significant page update Feb 2006 - rearranged each section into alphabetical order, added DIY heatsinks./ Jan 09 - added Glass-G./ Aug 09 - added active filter article./ 06 Jan 11 - Compound vs Darlington./ Jun 12 - Speaker failure + MOSFET relays./ Dec 12 - State-variable filters + VCAs.