The Valve Wizard

Putting the science into mojo since 2005. Last updated: 30 October 2011

New book: Designing Power Supplies for Tube Amplifiers. OUT NOW!

YOU'VE SEEN THE WEBSITE, NOW READ THE BOOKS!

Click the images to find out about the books.

NEWS: I am aware that some of the pages and images on this site are doing things they shouldn't. This is due to my web host software suddenly becoming case-sensitive for no apparent reason (and me being a poor html programmer). I am working slowly to fix this.

Update for my readership, July 2011: I have received several emails asking if I will be writing a Power Amps book to go with my other two books. The answer is yes, but it will NOT be on the shelves very soon! Building, testing and writing about power amps is a much more laborious and expensive affair than preamps or power supplies, plus I have some personal responsibilities now that I didn't have when I wrote the other two books. It could easily be three or four years before I complete the trilogy!

Introduction

Welcome to the wonderful world of valve amps! If you're here then you're probably thinking about tinkering about inside one. Building your own guitar amp is a rewarding pastime, but learning how to do it can be time consuming and frustrating sometimes. It is relatively easy to find introductory information on how to design simple amplifier stages, and it is also fairly easy to find extremely advanced information on complex circuit design, and nearly all of it is intended only for hifi! This website aims to fill the gap between the two extremes. I have also tried to remove unnecessary maths and leave only the essential formulae and rules of thumb. This should make the design process quicker and less confusing, leaving more time for the actual building. However, this site assumes that you know some basic principles already, like Ohm's law, roughly how a valve works, etc. If you don't know these things yet then I recommend you read some introductory electronics material. Even so, I have done my best to write these tutorials cook-book style so that even a layman can follow the instructions and design a working circuit without actually knowing how it works- but it certainly helps to understand first. Although aimed specifically at designing guitar amplifiers, principles of hifi have been included here so that audiophiles may find something of use too, and guitarists should be able to learn some of the science behind the mojo.

Disclaimer: Building and modifying amplifiers is DANGEROUS (like most fun things). Valve amplifiers invariably contain both very high voltages and high currents, capable of killing you. Whilst anyone can learn the skills to build an amazing amplifier, it goes without saying that you must never work on a live amplifier! I provide the information on this site free of charge, and it is up to you to exercise caution and common sense at all times to avoid electrocuting yourself, and make your amplifiers safe to use. I am not responsible for your negligence. Building valve amplifiers is also more addictive than nicotine; you have been warned.

This site is always under construction.

Contact: Suggestions, comments, criticisms welcome. I am also available as an amp tech in York, Yorkshire.