The Jazz Guitar Sound
The Science of Warm & Mellow
Jazz guitar seemed to come of age somewhere around WW II. Charlie Christian and Django Reinhardt gave it a big boost in the pre-war years but it was after WW II that the number of Jazz guitarists seemed to proliferate suddenly and this instrumental style found its voice in the guitars and amplifiers of the era.
This era saw the guitar finish its migration from the rhythm section to being a solo voice as small groups became more popular and big bands began to fade away. While 1939 was a significant year in gutiar development with the L-5 and Super 400 Premier modernizing these classic models the post-war years saw the cutaway electric archtop become the mainstream instrument. The nearly ubiquitous ES-175 came out in 1949 and all but defined the genre for players with moderate budgets. The long term effects of the post-war Jazz guitar era are still felt 60 years later.
An Un-Effected Presence
Starting in the '60s, effects became something an individual could own instead of something confined to a commercial recording studio. Guitarists from that era forward have bought untold numbers of effects ranging from somewhat cumbersome and expensive devices in the '60s to the incredibly inexpensive but good sounding multi-effects devices of the early 21st century.
When guitarists of our day hear a guitar sound it's only natural to try to analyze it in terms of effects involved. To guitarists today it may be surprising to learn that many of the Jazz players of the post WW II generation were not admirers of any kind of effects. One of my former instructors is very typical of the breed. He played a 16" archtop with a single pickup through a Gibson GA-50 amp. He considers reverb an effect and he is, of course, right about that. It's just that most of us never think about reverb beyond deciding whether to set the knob at 3 or 4 or 5 or whatever. He does use chorus from time to time but I don't think that he likes it very much. This is not because of stodginess or narrow-mindedness, it's just that the goal when he was developing as a guitarist was to preserve the natural sound of the guitar first and foremost.
My point here is that the thinking of that generation of players is so categorically different from the thinking of the newer generation of players it is hard to imagine. Even though I'm into Jazz guitar and studied with players that had that way of looking at things I was also exposed to Duane Eddy, Link Wray and Surf guitar from the early '60s. To me, the sound of the electric guitar was natural and reverb was always a matter of "how much", not "should I use it".
Guitar Pickups
Floating pickups were used as a way to preserve the characteristics of huge rhythm boxes to the greatest extent possible as an electric guitar became a necessity. There were two diverging schools of thought at work at this time. One was to build archtops that preserved the acoustic qualities of the rhythm guitars and the pickup was added on in such a way as to not interfere with the movement of the guitar's top.
Starting with D'Armond Rhythm Chief pickups added to D'Agelicos and prehaps culminating in the Gibson Johnny Smith model, a purpose-built acoustic archtop with an Epiphone style mini humbucker solidly mounted to the end of the fingerboard. The other school of thought started with archtops with parallel bracing and pickups cut into the top. A lot of people don't realize that an L-5 CES is structurally quite different from an L-5 C, employing different bracing and a degree of built-in feedback resistance.
When the ES-175 was first produced in 1949 it had a single P-90 pickup. This was truly a departure from the floating D'Armond that was so common at the time. The P-90 was a very warm sounding pickup and didn't produce the amplified sound of a big rhythm guitar but instead produced a somewhat less defined sound that was perfect for making single-note lines sound full. Chords tended to sound a bit less defined than the rhythm guitars of the big band era and it was not unusual for Jazz players to turn the volume down and comp acoustically if the venue size was such that they could be heard acoustically.
One interesting side effect of this was that chord-melody playing tended to sound run together, almost mildly distorted. This sound worked beautifully for mellow ballads and probably gave impetus to the proliferation of Jazz guitar trios with a guitar holding down both the melodic and harmonic center of the song while the bass and drums kept the rhythm intact. It is this sound that first attracted me to Jazz guitar and I still think of it as a very high expression of the guitar player's art.
Guitar Tops
Laminate tops were found to be less feedback prone than solid tops so the L-4 found itself with a laminate topped sibling, the ES-175, a guitar that has been used by many prominent Jazz guitarists over the years. It's not widely known, but both D'Angelico and D'Aquisto made laminate guitars for their customers and I assure you, their customers weren't trying to save a buck. Laminate archtops are very useful when gigging in a venue larger than some tiny hole in the wall Jazz club. It is my opinion that this school of thought reached its full expression in the ES-335 which, in my humble opinion, is the perfect hybrid of an archtop and a solid body. It maintains enough acoustic function to be playable without an amp at living room volumes but at gig volumes it functions with feedback resistance approaching that of a solid body.
These guitars and similar designs of all makes are renowned for versatility and can sound convincing in a wide range of roles ranging from Jazz guitar through Blues to no holds barred Rockin' out. I recently played the only ES-335 style guitar ever made by Bob Benedetto and it was superb.
There's more about this subject in the Laminate vs. Solid page on this site.
Amplifiers
Amplifier choices also seemed to fall into two camps. The amps Gibson made back in the day were dark and probably shaped the development of Jazz guitar sound to a great degree. I don't think that these amps were prone to overdrive, they were low-stressed devices that were quite different in design than the Fender designs that followed. They had 6SJ7 pentode tubes in the preamp and a very simple overall circuit design. The entire concept was different from Leo Fender's approach to amplifier design and the results were likewise dissimilar. These amps seem to reflect the conservative nature of Gibson's guitars while the Fender amps fit the much less traditional approach that Leo Fender used in his guitar-making.
Much like the two schools of archtop design these two schools of amplifier design followed their own directions. Fender amps continued to evolve towards the clean sound of the Blackface era and some Jazz guitarists followed. Wes Montgomery was known to use Fender amps as well as the ultra-clean Standel amp. Johnny Smith favored a bright, clean sound and eventually had a solid state amp built by an electrical engineer in Englewood, Colorado, the perfect tool to give him his desired sound.
Overdrive
I've heard the classic Jazz guitar sound described as being just on the brink of breakup but this has never been my take on the matter. Let me explain.
Speaking in terms of a clean amplifier as the volume increases the highs can become very shrill, something I like to call the "ice-pick effect". I can recall playing a Stratocaster in a small venue and finding that the highest notes were uncomfortable for me on stage. I could only wonder how they affected the audience. Amps turned up past their maximum clean volume will break up and this has a smearing effect on the notes. By nature this will counteract the ice-pick effect and untold dollars have been spent on effects to accomplish this in a controllable manner at volumes well below the maximum clean volume of an amplifier.
With Jazz guitarists a warm, mellow sound was also desired in most cases and usually easily accomplished. Here is a perfect example of the different mindset that the post war generation guitarists had in comparison with the guitarists raised in the Rock 'n' Roll era. Many of the Jazz players that became prominent in the '50s were playing ES-175s with the guitar's tone control rolled back. In some cases they had it rolled back as far as it would go effectively eliminating most of the upper order harmonic overtones. Doing this is nearly an anathema for most Rock players where the emphasis is on maximizing the harmonic output of the instrument and enhancing these in the amplifier.
It is my opinion that what some hear as the edge of breakup is, in fact, just a guitar with the tone turned out quite possibly amplified by an amp with the bass turned up. Even a fairly harsh sounding solid state amp will sound warm under these circumstances and no overdrive is needed.
