Report Review for product Guitar Amplifier Design: Tubes and Semiconductors Play Together

A ground-breaking approach to modern state-of-the-art Guitar Amplifier Design – a “must-read” deserving of a place on your reference book shelf.
There’s an old adage that says “You can’t judge a book by its cover”. If you took a quick look and decided to give it a pass, concluding that cartoon characters on the front cover don’t spell “serious” - you missed the boat. Take another look - Vacuum Tubes and Semiconductors “playing” together in a Guitar Amplifier - this book is ground-breaking in its approach to the design of a modern state-of-the-art guitar amplifier.
There are numerous books on the market which discuss and dissect designs from the tube amps of the 50’s to the digital modelling amps of today – this isn’t one of them. In this book, the author starts with a blank sheet of paper and the premise that “tubes and semiconductors are complimentary and used together provide a powerful suite of solutions to achieving his Guitar Amplifier Design goals and objectives.”
Step back for a moment and consider the statement “Any good electric guitar amplifier is designed to produce distortion”.
Many players consider solid-state amplifiers to sound “thin, lifeless and buzzy”, preferring tube amplifiers specifically for the characteristic overdrive distortion which can be produced by their vacuum tube circuits. That said however there are applications within an amplifier in which today’s semiconductor technology can clearly outperform that provided by tube technology. What then if one selects applications and combines optimum choices from among the palette of available options which technology provides? Semiconductors for signal amplification, vacuum tubes for overdrive, tone, colour and presence.
This is the approach taken by Neumann as he carefully walks the reader stage-by-stage through his design process, from input, through tone and phase inverter, to output, using interconnected vacuum tube and semiconductor technology to achieve his end goal. But there’s more.
Remember the weight of your existing amp? Why is it so heavy? The answer of course lies in the fact that it utilises at least two transformers mounted on a steel chassis. What if one could eliminate the transformers and build the amp in a lighter weight aluminium chassis? Well, by adopting a switching power supply and an AOT (Active Output Transformer) design using active components to mimic the behaviour of an output transformer, the author has done just that. How about a finished 100W amp weighing less than 7 lbs?
Even if you don't decide to build one of these amplifiers, this book will open your eyes to the “art of possible” and why technology integration should be considered. This is your opportunity for a first-hand preview of what the next generation of guitar amplifiers are going to look like.
The bottom line for anyone with an interest in guitar amplifiers is that this book, “Guitar Amplifier Design” is a “must-read”, deserving of a place on your reference book shelf.
Conclusion: When looking for a book to buy and read, the first thing that probably grabs your attention is the cover. If the cover appears uninteresting you will probably conclude that the book is not for you and move on. However, if you open the book up and read what is inside, you may find it pretty interesting after all. The old adage is correct – outward appearances are not a reliable indication of that which resides within.
Footnote: I previously purchased and very much enjoyed reading an earlier 2015 book by Ulrich Neumann and Malcolm Irving, entitled “Guitar Amplifier Overdrive – A Visual Tour”. It currently resides on my reference book shelf.
Armed with this knowledge, and what ever she thought of the cover, my wife purchased “Guitar Amplifier Design” giving it to me as a Christmas gift. I’m very glad she did. It is indeed a “serious” book. It too has earned its place on my reference book shelf.

David R. Anderson, P.Eng.
April 2020