The Ultimate Tone – A Book Review of the Best DIY Guitar Tube Amplifier Series

This article is a book review on a series of six books that is the most comprehensive and lucid explanation of guitar tube amp architecture, circuits, tone, components and construction technique for DIYers I have ever found. The review deals with each book separately and recommends purchasing them in a specific order to grow 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 unique and carefully tailored for the Do-It-Yourself (DIY) guitar tube amp hobbyist and boutique amplifier builder. The books have a home-made ‘feel’ as well… all the illustrations are done by hand and the books are photocopy-printed 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 being released in the late spring of 2008. You may want to buy the entire series all at once and get a modest savings, but I think you should consider buying them one at a time and digest as you go, building projects along the way. A key point though… you don’t necessarily want to buy them in numerical order. I recommend the following sequence:

1. The Ultimate Tone Volume 3 – Generations of Tone
2. The Ultimate Tone Volume 5 – Tone Capture
3. The Ultimate Tone Volume 2 – Systems Approach to Stage Sound Nirvana
4. The Ultimate Tone Volume 4 – Advanced Techniques for Modern Guitar Amp Design
5. The Ultimate Tone – Modifying and Custom Building Tube Guitar Amps
6. The Ultimate Tone Volume 6 – Timeless Tone Built for the Future Today

The Ultimate Tone Volume 3 – Generations of Tone

This is the most important book in the series for the beginning tube amp builder.

Chapters 2 through 4 lay down the foundation of good DIY tube amp construction, filling you in on good electrical connections, grounding technique, lead dress and other wiring techniques, and mechanical layout including assembly methods like terminal strips, turret and eyelet boards.

The subsequent chapters each pick a particular ‘iconic’ amplifier, each iconic amplifier being a prototypical example of amplifiers of its class, and they are examined in detail as to the circuit topology, peculiar tonal characteristics that result and fatal flaws that the product is notorious for. Kevin provides the original schematics and then shows how you can apply the techniques detailed in the earlier chapters to improve the performance and reliability of the icon without harming the tone. The schematics are redrawn, layouts are provided and mechanical solutions are worked out to make each chapter a complete, self-contained, build-it-yourself amp project.

This process is repeated for several variations of the Champ in chapter 5 (this chapter greatly influenced my own single-ended amp project), then in quick succession: the Bassman, Plexi, 800, Bull Dog, AC-30, Portaflex, SVT, Bass Master, Custom Special, Guitar Mate, Herzog and Laney amplifiers are dealt with.

If you can only buy one book for your DIY guitar amp hobby I’d heartily 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 starts off with a chapter overviewing vacuum tube operation called ‘tube tone,’ followed up by a chapter on guitar electronics and pickup characteristics.

The next two chapters are small projects: Sigma for effects switching and Triple-X for amplifier switching.

Chapters 5 & 6 are on 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 (the London Power Standard Preamp from 1995 coupled to a 50W amp using four power tubes), Doppelsonde (mixing power tube types), AX84 (discussion on the original goal of a very low output power amp), Kelly (50W from 4 6V6s), and several other projects of lesser scope.

One favorite project I did was based on Kevin’s reworking of the HotBox tube preamp pedal from Matchless in chapter 16. I built this pedal in a truly “true point-to-point style” (meaning terminal strips) in a tube pedal enclosure from Doug Hoffman, substituting a Baxandall tone stack and reworking the preamp values to be more Dumble-esqe (non-HRM type).

What would you do to match an amplifier to Yngwie Malmsteen’s style? See chapter 18, ‘Swede.’

The Ultimate Tone Volume 2 – Systems Approach to Stage Sound Nirvana

Volume 2 is not project oriented. The bulk of the book, chapters 2 through 5, deals with power supply tricks and a comprehensive overview of power amplifiers, including tube, solid-state and hybrid power amps. Chapter 3, on tube power amplifiers, has some very practical information on mods and fixes to Marshall and Fender bias circuits.

I like the 1st and last chapters of Volume 2 the best. The first chapter is a short discussion of sound stages and how you might setup your gear on stage for the best audience/band experience. The last, chapter 6, is called “Pillars of Tone” and in this chapter the major contributors tone at the block-level of a guitar tube amplifier system design are discussed one by one and Kevin provides some very valuable insight into tone shaping throughout the preamp/amplifier.

The Ultimate Tone Volume 4 – Advanced Techniques for Modern Guitar Amp Design

This is the book you’ll want to buy if you feel the need to get deeply involved with the power scaling technology that 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 DIY project oriented but explores the issues, including attenuation, power scaling (both down and up), sag, and power management, tackled by modern guitar tube amp designers.

That said, the second-to-last chapter in Volume 4 might be important for a broader group of enthusiast builders… design philosophy. In this chapter Kevin provides a hierarchical design process that could be used to make key decisions on how you approach your next project.

The Ultimate Tone – Modifying and Custom Building Tube Guitar Amps

There is no volume number in the title of this book, it was the 1st. Personally, I bought it for completeness. I specifically wanted to have the ‘perfect effects loop’ information, although the loop itself is incorporated into a project in Volume 5. TUT also has some excellent material on reverbs and signal switching methods that is not explained in the other volumes. The first half of TUT introduces/overviews tube amp systems, power supplies & grounds then focuses on preamp and power amp modifications to commercial amplifiers (e.g. Marshall / Fender)… if you are totally new to tube electronics you may want to buy this 1st volume at the same time as Volume 3.

The Ultimate Tone Volume 6 – Timeless Tone Built for the Future Today

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 featured which was introduced in Vol 4 but flushed out with comprehensive circuits and applied to ‘sag’ and sustain control as well in Vol 6.  The new scaling circuits have many advantages for a DIY builder like greater noise immunity and less sensitivity to layout, 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 just too loud for domestic use, needing to be cranked to get the sweet tones it is renowned for.

One of the chapters in Volume 6 is dedicated to the Dumble amplifiers… something I was really looking forward to since many of my hobby projects focus on those circuits.  I found this short chapter to be a good introduction to the overall architecture of the Dumble amps, written from the point of view of the evolution from the early modified standard amps that Alexander Dumble started out doing, but I felt the chapter fell short in discussing some of the more important subtleties of the later Dumble models.

Volume 6 also has lots of other material in it, including a great tutorial on designing really high output power amplifiers and a great chapter on high gain amplifier designs with real-world circuits referenced and detailed.

In Summary…

Kevin’s books have a very empirical approach. He encourages you to set aside convention in some instances or not be afraid to try combinations of tubes or even pulling tubes and in all cases clearly explains why it is o.k. and points out any reasons why it wouldn’t be o.k. All the examples in the books are very practical and he certainly has the DIYer in mind as he is writing.

Kevin’s body of work is truly encyclopedic in nature, and considering that, one feature sorely lacking from his books is any kind of indexing… this is aggravated by the fact that Kevin constantly refers to previous writings rather than repeat himself in a new volume, and it is very difficult to put your finger on the reference even with the other book in hand. Perhaps search engine technology, like Google’s ability to search protected content, could be put to good use in this case and provide a kind of ‘auto-index’ on the web of all of Kevin’s books without actually giving away the book itself. Or better yet, how about an e-book format of Kevin’s entire collection of TUT books… I think all of the e-book readers include searching capabilities… and Kevin’s hand-drawn schematics would probably scale adequately and be very readable on the e-paper displays these devices feature.

Meanwhile, how do you get Kevin’s books today? The best way to get the books is to directly order them from London Power Press. They now have a shopping cart on http://www.londonpower.com.