The Audio Pages

This Page Is Updated Regularly
Last Update March 2023

The projects presented here are a mixture of basic and complex designs.  Of these, most are originally designed by me, and have some unique quality which makes them worthy of publication, while others are simple extensions of basic theory.  Not all have been built and verified, but with those that have not this is not an issue, since they cannot help but work.  Of those which are not tested, they have all been simulated to verify that no stupid mistakes have been made, and will work on the first attempt ... if correctly built with the component values shown .

In general, these projects are not intended for the novice electronics hobbyist, since they all require some basic (or in some cases advanced) knowledge of electronic circuit construction, mounting power transistors, soldering techniques, mains wiring, etc.  Make sure you read (and heed) all warnings and the disclaimer before starting construction.  Some are very straightforward though, and are suitable for beginners - provided you already know basic theory, component types, and know how to solder properly.

Main Index
Numerical Projects Index	(With brief description)
Category Projects Index	(With extended description)
Complete ESP Pricelist

	Project Type	Comments
	All projects in numerical order	Includes brief description
	Power Amplifiers and Accessories	Power amps, supplies, indicators, soft start, etc.
	Headphone Amplifiers/ Adapters	Adapt power amps for headphone use, build dedicated headphone amps
	Preamps and Accessories	Preamps, tone controls, equalisers, phono, etc.
	Crossovers and Effects	Electronic (active) crossovers, limiters, filters, etc.
	Power Supplies	Power supplies for preamps, power amps and power switching systems.
	Musical Instrument	Guitar, bass and keyboard amps and accessories.
	Mixers, Meters, Microphones, etc.	Mixers large and small, metering amplifiers, phantom power, etc.
	Digital Audio Applications	Just like it says ... (not much to see though).
	Test Equipment	Measurement systems, including meters, oscillators, etc.
	Microphones and mic preamps	Again, just like it says ...
	Miscellaneous	Anything that doesn't fit into the main categories above.
	Lighting	A small selection of lighting effects (desk, dimmers, etc.)
	Loudspeakers	Subwoofer/ woofer equalisers.
	Browse	Look through the various categories

Each project description may have one or more 'flags', that indicate the status of the project itself.  The flags are as follows ...

	Flags	Description
		The design (or update) is less than 2 months (or thereabouts) old.
		There has been a update of sufficient importance to make sure that you know about it.
		Mains wiring is involved, and is potentially dangerous - heed all warnings ! Note that this symbol is displayed on specifically mains powered projects, but other projects may also need a power supply which also requires mains wiring.
		PCBs are (or will be) available for any project marked with this symbol. Boards may not be available immediately, but are expected within a month of publication of the project or posting of the PCB symbol.
	Date	The page was added or updated on the date shown (new updates are shown in red)

ESP reserves the right to change or update projects without notice, so it is important to be aware that a change may have been made.  You should always watch for updates of previously published items.  These are shown as a date beside the project (in the "Flags" column). Do not build any of the circuits presented here without checking for updates first.  A 'new' symbol indicates an update within the last two/ three months or so (but this might vary).  Special cases might be listed from time to time - these are likely to be important! Updates less than 3 months old will have the date in red.

Please see the ESP disclaimer for important information

WARNING Mains wiring should be carried out by suitably qualified persons only.  Under no circumstances should any reader construct any mains operated equipment unless absolutely sure of his/her abilities in this area.  Death or serious injury (to the constructor or others) may be uncommon with home construction of mains powered projects, but the risk is ever-present.  The author takes no responsibility for any injury or death resulting from, whether directly or indirectly, the reader's inability to appreciate the hazards of household mains voltages and the correct wiring practices for your country.  Please read the disclaimer now if you have not done so already.

Although I am happy to provide assistance to prospective builders, I cannot (and will not) be drawn into prolonged e-mail exchanges if the project does not work as expected.  I can say with complete confidence that all projects presented will work ... if properly constructed according to the published design.  This is not to say that no help will be available - I will help where I can.

It is inevitable that in some cases (due to component tolerances, for example), a project may require a different value resistor, capacitor (or whatever) to correct for an unexpected variation.  Since I cannot control or predict the quality of components sourced by readers, nor the standard of workmanship in assembly, it is not possible to allow for every contingency.

Please do not attempt the construction of any project which you do not fully understand, or if you do not feel completely confident that you can build the project without further assistance.  Do not expect me to be able to diagnose an obscure fault remotely, and especially if the project has been modified in any way whatsoever.

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