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Chris's Fender Classic Vibe 60s Jazzmaster Modification

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Fender 
Vintera Series Jazzmaster   American Performer Jazzmaster

Part One: Jedi Guitar Tricks and a New Hope for an Old Martin 

 

“That’s no moon. It’s a space station.”

                            Obi-Wan Kenobi, Jedi Master

It was a dark and stormy day when I acquired my 1967 Martin D12-20.  That’s a lie.  It was a perfectly normal, sunny, spring day, punctuated with slightly muted farting horn voluntaries coming from the cars piled up in the daily lunchtime Atlanta gridlock outside—but, brainstorms were on the horizon!  Meanwhile, I was reluctantly parting with some cash to add a vintage 12-string that I didn’t really need to my collection (of course, as we all know, need is rarely a factor where guitar purchases are concerned.)  The gentleman standing before me had stopped in a month or so prior to have his D12-20 appraised and to discuss its possible sale to the store, all in the hopes of raising some much needed funds for textbooks.  At the time, we had to passed on the purchase, as his old Martin was in dire need of a neck reset and numerous other structural repairs.  In all fairness, the guitar could have been restored and sold at a profit. Yet, after weighing the cost of the repairs against the relatively modest market value of the guitar, I had determined that a wholesale offer would have been quite low, possibly insulting.  Subsequently, I advised the gentleman to attempt selling the guitar as-is with all known issues disclosed, as I felt that was in his best interest…but, before I fully realized what I was doing, I also kind of let it slip out that I would personally consider the guitar if he didn’t have any success selling it elsewhere.  Well, now I was answering for my rash moment of sympathy and honoring my word to purchase a guitar that, to my surprise, was actually in worse condition than I had remembered!  

Now, as a man with lighter pockets, and as the proud owner of a non-functioning Martin 12-string, I found myself confronted with a bit of a dilemma.  I already owned a fully-functional Taylor 655C 12-string.  Thus, I wasn’t particularly excited by the prospect of investing another hefty sum to address the myriad issues plaguing this dilapidated Martin only to end up with another 12-string. On the other hand, my pragmatism and irrational tendency to personify and pity neglected instruments precluded me from owning any guitar that couldn’t be put to use!  Possessing a borderline mystical degree of expertise in the realm of procrastination (e.g., I once convinced myself that watching Star Wars for the umpteen billionth time was tantamount to studying for a midterm on Chaucer), and having a better than average awareness of the Force (thanks to my strict procrastination regime), I determined that the most responsible course of action was to do nothing while the Midi-chlorians worked to resolve the matter for me. (For those less familiar with Star Wars lexicon, Midi-chlorians are sentient microscopic lifeforms that enable one to sense and channel the Force.)

After a sufficient period of procrastination had elapsed to allow a healthy measure of guilt to fester in me, I resolved that I must do something with this unusable guitar!  Evidently, prioritizing the teachings of Obi-Wan Kenobi over the inscrutable middle English parables of the Canterbury Tales was a good decision, as the Force guided me to an unlikely solution to my quandary over the fate of the D12-20:  While re-assessing the guitar’s numerous issues and grimly tallying up the projected repair cost, I was suddenly overcome by a powerful feeling of providence unfolding before me as a wild idea took hold. I thought to myself, “that’s no 12-string, it’s a baritone!” 

Now, was I certain whether this concept was actually feasible? No. But, if my Jedi guitar training had taught me anything, it was that I should trust my feelings. Of course, in this case such instincts are built upon a great deal of insight accumulated over many years in the guitar business!  For instance, I have frequently encountered efforts to convert a 12-string guitar into a 6-string guitar. Folks usually attempt this for one of two reasons:  1) they have no money to invest in the 6-string that they want, but they happen to have a 12-string handy; or, 2) they have a high-quality 12-string (like an old Brazilian rosewood Martin) and they are hoping to create a great-sounding 6-string by exploiting the purported sonic potential of its premium tonewoods. In either case, these hopeful guitar enthusiasts are almost invariably disappointed when they encounter the harsh reality that their 12-string is more heavily braced than a 6-string guitar and is therefore not very responsive with the tension of only six strings tuned at standard pitch.  

Meanwhile, I knew that a lower tuning could work pretty well on a 12-string guitar under the right circumstances. One of my heroes, Leo Kottke (a.k.a. Leo Kenobi, for the sake of this article’s humor continuity), tunes his 12-string guitars down to C#. Yet, old Leo Kenobi is clearly aware that one must maintain balance in the force whenever making such adjustments, as he uses heavier strings to compensate for the loss of tension at such a low tuning—  

WE INTERRUPT THIS AUTHOR’s ANECDOTAL MUSINGS FOR THE FOLLOWING GUITAR ENTHUSIAST’S PUBLIC SERVICE ANNOUNCEMENT REGARDING STRING TENSION:

“Did you know that your guitar’s soundboard needs a certain amount of string tension in order to project with any strength? This tension is primarily determined by four factors: the gauge of the string, the material from which the string is made, the scale length or distance over which the string is stretched, and the pitch to which the string is tuned.  You should also be aware that another factor can come into play where wound strings are concerned. Though two strings may measure the same gauge or thickness, the ratio of core wire gauge to wrap wire gauge could differ and therefore translate to different tension (the string with a heavier core wire will typically be at greater tension at the same pitch).  Thus, in the design of stringed instruments, one must always account for the relationship of pitch, string length, and string gauge.  Our friend the piano is a grand example of these relationships at work: As pitch increases, string length shortens and string size diminishes to mitigate the increasingly high tension (which can wreak structural havoc!). Whereas, decreasing pitch necessitates thicker strings that are stretched further in order to generate enough tension for the lower pitch to be projected and sustained. Wow, who knew that strings or pianos could be so interesting?!”

NOW, BACK TO YOUR NOT-SO-REGULARLY SCHEDULED NEWSLETTER…

 Despite Leo Kenobi’s valiant use of the Force, there are limits to what one can achieve with string gauge alone. To properly support their low tuning, most baritone and bass guitars not only use really heavy strings but also have long scale lengths/necks.  The typical baritone scale length is approximately 28.5” – 30”, which can translate to some pretty tough stretches for mere mortals attempting to play anything more complicated than simple chords or melody lines. Yet, in recent years some companies have created baritones with a much more manageable 27” scale length.  In my mind, Taylor Guitars created the first acoustically viable version of this design with the introduction of their 8-string baritone, the GT-8, at the 2010 winter NAMM.  I have long been interested in baritone guitars; but, to be totally candid, I’ve never encountered an acoustic baritone or bass guitar that could compete with a great acoustic guitar when it comes to filling a room.  Any that have come close to delivering a satisfying acoustic experience have been invariably bulky and cumbersome (the best among these are probably the now-defunct Tacoma Thunderhawk and Thunderchief).  Yet, in playing the Taylor GT-8 at that tradeshow, I was immediately struck with the guitar’s ability to project, despite its shorter 27” scale. Afterword, it was undeniable that a decent baritone could be made with shorter scale length than what common wisdom would have suggested.

The precedent set by the short-scale GT-8 aside, the guitar that would become my “secret weapon” 8-string baritone was the result of a number of factors (apart from the Force): a general grasp of string tension math, an exposure to many failed 12-string to 6-string conversions, a dorky baritone guitar fetish, and, most importantly my understanding of 12-string guitar design.  This last factor was the most significant, because it was here that I discovered a work-around for creating the string tension necessary for a useable baritone tuning on a guitar that was in no way intended to be tuned so low.  

First of all, 12-strings are braced more heavily to accommodate the additional tension of the extra strings they support, so I reckoned that the D12-20 could probably handle the tension exerted by a baritone string gauge. More importantly, the 12-string design requires six additional string anchor points. It occurred to me that if only six or eight strings were being used, I could extend the length of any given string on my D12-20 if I were to anchor them at the guitar’s extremes. Indeed, by using the rear bridge pin positions and the top tuning posts, the string length was increased by roughly 1 1/2 inches (or possibly 2 inches, if I were to only use 6 strings).  Furthermore, in this case the D12-20’s slotted headstock would afford a subtle increase in tension compared to a solid headstock, given that the string has a greater break angle as it passes through the headstock to the tuning post. True, the sum of these various increases in length does not quite equate to the overall string length of most baritones (once you factor in the extra distance to their anchor points), but it’s pretty darn close.  Finally, though unrelated to the general concept of the conversion, I also saw an opportunity to possibly bypass the immediate need to reset the guitar’s neck, in that baritone tuning often requires a slightly higher action, which the D12-20 could certainly accommodate at the time! 

Taking all of this into consideration, I figured the experiment was worth a shot, and in the time-honored tradition of a Jedi forging his light saber, I set to the task of crafting my own 8-string baritone. After making a custom nut, and putting on a fresh set of strings, I was pleased to discover that my instincts were correct. More importantly, I quickly realized that I had also stumbled onto a method for creating an acoustically-viable baritone with a standard guitar scale length!  This was so exciting, that I promptly ponied up the dough to properly repair the guitar and dedicate it to its new purpose of projecting low frequencies to galaxies far, far away.

Now, in the end, I suppose brand loyalists everywhere will probably struggle with the fact that I ultimately combined Martin and Taylor designs—depending on one’s allegiances, this could be construed as a powerful disturbance in the Force.  Yet, combine them I did, and the result is beautiful. Thus, hopefully any objections will fall to the side and my story will serve to instruct and inspire others to try their hand at similar conversions. Regardless of whether you embark on such an endeavor, I wish you well in your guitar journeys, and may the Force be with you!  - L. Petsch, February, 2022