This article is a review of a six-book series that is the most comprehensive and lucid explanation of the architecture, circuitry, tone, components, and construction technique of do-it-yourself tube guitar amps that I have found. The review treats each book separately and recommends purchasing them in a specific order to increase your knowledge in step with your building experience.
Kevin O’Connor of London Power has created a series of books under the main title of “The Ultimate Tone”. These books are truly one-of-a-kind and thoughtfully designed for the DIY tube guitar amp hobbyist and boutique amp builder. The books have a homey ‘feel’ too…all illustrations are hand drawn and books are photocopied on 8.5″x11″ paper and bound with plastic spines and clear plastic covers. There are six books in the series now, with the most recent released in late spring 2008. You may want to buy the entire series at once and get a modest savings, but I think you should consider buying them one at a time and digesting as you go, building projects as you go. One key point though… you don’t necessarily want to buy them in numerical order. I recommend the following sequence:
- The Ultimate Tone Volume 3 – Tone Generations
- The Ultimate Tone Volume 5 – Tone Capture
- The Ultimate Tone Volume 2 – Systemic Approach to Nirvana Stage Sound
- The Ultimate Tone Volume 4 – Advanced Techniques for Modern Guitar Amplifier Design
- The Ultimate Tone: Custom Tube Guitar Amp Modification and Creation
- The Ultimate Tone Volume 6 – Timeless Tone Built Today for the Future
The Ultimate Tone Volume 3 – Tone Generations
This is the most important book in the series for the beginning tube amp builder.
Chapters 2 through 4 lay the foundation for a good DIY tube amp build, giving you information on good electrical connections, grounding techniques, wiring and other wiring techniques, and mechanical design including assembly methods such as terminal strips, turret, and grommet boards.
Each of the subsequent chapters chooses a particular ‘iconic’ amp, each iconic amp being a prototypical example of amps of its class, and are examined in detail as to circuit topology, the peculiar tonal characteristics that result, and fatal flaws for which the product is notorious. Kevin provides the original schematics and then shows how he can apply the techniques detailed in the previous chapters to improve the performance and reliability of the icon without harmonizing the tone. Schematics are redrawn, layouts provided, and mechanical solutions worked out to make each chapter a complete, self-contained, build-it-yourself amplifier project.
This process is repeated for various variations of the Champ in Chapter 5 (this chapter heavily influenced my own single-ended amp project), then in quick succession: Bassman, Plexi, 800, Bull Dog, AC-30, Portaflex, SVT, Bass Master, Custom Special, Guitar Mate, Herzog, and Laney amps are covered.
If you can only buy one book for your DIY guitar amp hobby, I wholeheartedly recommend this one.
The Ultimate Tone Volume 5 – Tone Capture
Volume 5 picks up where Volume 3 left off, with a project-oriented approach and some sophisticated DIY tube amp solutions for guitar and bass.
The book begins with a chapter describing the operation of the vacuum tube called “tube tone”, followed by a chapter on guitar electronics and pickup characteristics.
The next two chapters are small projects: Sigma for effects switching and Triple-X for amp switching.
Chapters 5 and 6 are about transformers…important components but it made me yawn, sorry.
Starting with Chapter 7, all the stops are pulled out and you are in project heaven… Major (200W), Soma 84 (El84 amp), Standard (1995 London Power Standard preamp coupled to a 50W amp using oven power tubes), Doppelsonde (mix of power tube types), Ax84 (discussion of the original Put power amp), Kelly (50W of 4 6v6s) and various other smaller projects.
One of my favorite projects was based on Kevin’s reworking of the Matchless HotBox tube preamp pedal in Chapter 16. I built this pedal in true “point-to-point style” (i.e. terminal strips) on a Doug Hoffman tube pedal box, substituting a Baxandall tone stack and reworking the preamp values to be more Dumble-esqe (non-HRM type).
What would you do to combine an amp with the style of Yngwie Malmsteen? See chapter 18, ‘Swedish’.
The Ultimate Tone Volume 2 – Systemic Approach to Nirvana Stage Sound
Volume 2 is not project oriented. The bulk of the book, Chapters 2 through 5, covers power supply tricks and a comprehensive overview of power amps, including tube, solid-state, and hybrid power amps. Chapter 3, on Tube Power Amplifiers, has very handy information on modifications and fixes for Marshall and Fender bias circuits.
I like the first and last chapters of Volume 2 best. The first chapter is a short discussion of soundstages and how you can set up your equipment on stage for the best audience/band experience. The last one, Chapter 6, is called “Pillars of Tone” and in this chapter the major contributors to block level tone of a tube guitar amp system design are discussed one by one with Kevin providing invaluable insight into tone shaping throughout the preamp/amp.
The Ultimate Tone Volume 4 – Advanced Techniques for Modern Guitar Amplifier Design
This is the book you’ll want to buy if you feel the need to get deeply involved with the power scaling technology Kevin has developed. Power Scaling, coined and trademarked by Kevin, is the way you can get aspects of power amp distortion (as opposed to preamp distortion) into your tone at bedroom volume levels. Volume 4 is not geared towards DIY projects, but explores the issues, including attenuation, power scaling (both down and up), rolloff, and power management, tackled by modern tube amp designers.
That being said, the penultimate chapter of Volume 4 might be important to a broader group of enthusiast builders… the philosophy of design. In this chapter, Kevin provides a hierarchical design process that could be used to make key decisions about how to approach his next project.
The Ultimate Tone: Custom Tube Guitar Amp Modification and Creation
There is no volume number in the title of this book, it was the first. Personally, I totally bought it. Specifically, I wanted to have the ‘perfect effects loop’ info, even though the loop itself is built into a project in Volume 5. TUT also has some great material on reverbs and cue changing methods that isn’t covered in the other volumes. The first half of TUT introduces/reviews tube amp systems, power supplies, and grounding, then focuses on preamp and power amp mods to commercial amps (e.g. Marshall/Fender)…if you’re totally new to tube electronics, you might want to purchase this first volume at the same time as Volume 3.
The Ultimate Tone Volume 6 – Timeless Tone Built Today for the Future
In many ways, Volume 6 is a continuation and extension of the material in Volume 4, where Power Scaling is introduced. In Volume 6, a new ‘direct control’ version of Powerscaling is introduced which was introduced in Vol. 4 but removed with full circuitry and applied to ‘sag’ and sustain control as well in Vol. 6. The new scaling circuits have many advantages for a DIY builder, such as higher noise immunity and less design sensitivity etc.
I applied the new DC Power Scaling to a Trainwreck clone project and was really impressed with the improvement in ‘playability’ at lower volumes… the unmodified Trainwreck Express circuit is too loud for home use, so cranking it up is necessary to get the sweet tones it’s famous for.
One of the chapters in Volume 6 is dedicated to Dumble amps…something I was looking forward to since so many of my hobby projects focus on those circuits. I found this short chapter to be a good introduction to the general architecture of Dumble amps, written from the point of view of the evolution of the first modified standard amps that Alexander Dumble started making, but I felt the chapter fell short in discussing some of the more important subtleties of Dumble’s later models.
Volume 6 also contains many other materials, including a great tutorial on designing really high output power amplifiers and a great chapter on high gain amplifier designs with detailed referenced real world circuitry.
Kevin’s books have a very empirical approach. He encourages you to drop convention in some cases or not be afraid to try tube combinations or even pull tubes and in all cases he clearly explains why it’s OK and points out reasons why it wouldn’t be OK All the examples in the books are very handy and certainly has the DIYer in mind as he writes.
Kevin’s body of work is truly encyclopedic in nature, and considering that, one of the most lacking features of his books is any kind of indexing… this is compounded by the fact that Kevin constantly refers to earlier writings rather than repeating himself in a new volume, and it is very difficult to pinpoint the reference even with the other book in hand. Perhaps search engine technology, such as Google’s ability to search for protected content, could be helpful in this case and provide a kind of “automatic index” to the web of all of Kevin’s books without giving away the book itself. Or better yet, how about an eBook format of Kevin’s Complete TUT Book Collection… I think all eBook readers include search capabilities… and Kevin’s hand-drawn schematics would probably scale appropriately and be very readable on the ePaper screens these devices present.
Meanwhile, how do you get Kevin’s books today? The best way to get the books is to order them direct from London Power Press. They now have a shopping cart at http://www.londonpower.com.