All our Instruments are built according to the old Spanish technique
The basic structure of all Thomas Guitars, are made by employing the old Spanish method of using a solera to glue the unfinished neck with the intended angle to the soundboard. Then the bent sides are glued with individual wooden blocks to the top, and finally the back is fitted.
This method has some really great advantages both tonally and structurally.
We make laminated quarter sawn necks, and a flat sawn block to connect the neck and foot. This block prevents the foot from being pressed out of the back over time due to wood shrinkage and expansion from varying temperature and humidity changes.
Before gluing the fretboard we install two carbon rods and a stainless steel truss rod. The carbon rod simply stabilizes the neck and prevents the neck to rise and bend too much over the years. The wedge between top and fretboard has some great advantages. Structurally because the fretboard can be thinner, and by reducing the weight of the neck the guitar gets better balanced and at the same time the upper frets are a lot easier to play because the fretboard is elevated in the area of the soundboard
The fretboard is made of a quarter sawn piece of ebony or rosewood
The slots including the nut, and the shape are cut by CNC. That guarantees the perfect position, hides the fret ends and allows the nut to become part of the fretboard for better sounding open strings.
We sometimes use different woods but we still favor Alpine Spruce from our area as these are exactly the same places where the old master luthiers Stradivari and Guarneri got their wood. Since 2010 we´ve been chosing the trees in the summer and cutting them at a particular time in the winter considering the phase of the moon, following the rules of the old grand masters. The wood is directly cut into pieces and naturally dried. The spruce cut after these simple rules becomes harder and lighter and tends to move less than ordinary cut spruce.
ABOUT FOUR PIECE TOPS
One of the most difficult tasks of luthiery is to obtain a constant tone quality. The easiest way to achieve that is to use the same wood with the same specs, but of course it is nearly impossible to get two similar Tops, even within a single tree.
In 2015, we decided to build a steel string double top guitar. Our goal was to find out how the tone is affected and if that change would be a possibility to create the sound we were looking for in an easily reproducible way. We used the common honeycomp - method as invented by Matthias Dammann with the inner and outer layer in moonspruce.
Since this guitar served as a prototype and we refused to waste two of our nice tops, we decided to assemble the inner layer of three spare parts. Surprisingly, we found out that the more inner layer was stiffer and homogeneous than the outer layer – which brought us to the idea of using only the best part of each board for cutting tops. No sapwood, no wider grain from the early years of the tree, just the „filet“ in-between.
The trees we cut are about 250 years old and 85cm in diameter so if you cut the sapwood and the core and the wider years from the inside, you get about 10 to 14 cm wide – „four-piece-tops“, which are very constant in stability and weight.
The X – bracing we use is not just a copy of an old Martin Guitar, but has rather evolved through the years with our ideas of sound and stability. Each model has a particular bracing that is shaped to a certain tone and stiffness.
We bend our sides on a self-made bending machine with a very accurate temperature limit for each different kind of wood and “bake” them until they become harder and stay in shape.
One advantage of using a solera for construction is the tension free assemble of the sides and soundboard. After being bent the sides are trimmed and glued into the slots in the heel, and then fixed to the top with small individual blocks.
Our backs are spherically domed with a 4m radius. After the sides have been tapered, we glue a reverse kerfed cedar lining and fit the back. As the back affects the timbre of the guitar, we work every back a little bit different to interact as well as possible with the neck and soundboard. In the case of bracing, we stick to 3 to 4 traditional scalloped back bars, or use a lattice bracing if the wood requires more longitudinal stiffness.
The bridge is cut of a quarter sawn piece of ebony. It is slotted in a way that the string is held even if you remove the pin and ramped that the string is guided to the saddle with a soft break angle. It will never happen to any of our guitars that the string will pop a pin out. You could play our guitars even with no pin in the bridge. We use the pins as fine-tuning like different materials for nut and saddle, not for fixing the strings in place.
We’ve invented this unique cutaway for structural and esthetical reasons. The idea is to change the angle formed by the slot in the heel to the central axis from nearly right angled to obtuse angled, and at the same time switched the position of the slot about 25mm on the top side facing the sound hole. As a result the heel is extended, due to its shape and the angle in a very special and ergonomically way. The advantages are that the heel cap could be normal sized, but the side is still straight and does not have to be bent in a 3rd degree. This simple trick keeps the normal sized and shaped heel, removes any tension of a twist-bended side and at the same time provides great access till the 20th fret.
We use a very thin Layer of pure polyurethane
lacquer applied and sanded in 8 different coats,
polished to high gloss, or finished with a matte coat at the end. The finish measures less than 1/10th of a mm so you can still see the structure of the wood but it is yet a great protection. Polyurethane has a great chemical resistance to moisture and perspiration even to alcohol, while it does not get as hard to change vibration or other tonal characteristics of the Instrument.
Though it gets slightly thinner over the years it will not
crack like nitro and keep its flexibility.
Within the years the “Barbera Soloist” has become our favourite Pickup for steel string and nylon string guitars. The focused tonal clarity, string to string balance and incredible power of projection it provides is truly a game changer for live performances with an acoustic guitar. Its design is very different from usual under saddle pickups, as it is an engineered saddle which contains micro electro acoustic structures within the saddle.
This allows for a directionally focused and refined sensitivity and fidelity of sound reproduction that does not amplify microphonic noise from the instruments surface.
Soloist pickups reject microphonic body noise, (finger noise squeeks, bumps, thumps, extreme low end boominess etc.) the elimination of this non musical noise in the amplified signal provides an extremely high level of clarity and tonal purity in the amplified sound. It also greatly decreases feedback sensitivity.
The saddles do not alter or detract from the guitar's acoustic sound. A passive installation allows for a wide range of external preamps to also be used or for preamp free usage when plugged into a guitar amplifier.