1. hobbies and interests
2. guitar

-1-
The Mechanics of the Acoustic Guitar
The principle by which all acoustic guitars produce musical sounds is generally agreed to
be the same. When you strike a guitar string, you
apply energy to it and make it vibrate. However,
this string vibration alone is not sufficient to create
sound waves in the surrounding air that can be
clearly heard.
In this respect, a guitar string can be thought of as
Tuning
being similar to a tuning fork. A tuning fork also
Fork
vibrates when struck, but it is virtually inaudible
until you bring it into contact with a mass of lower density (a mass with a whole lot more
surface area helps too), which can transmit the vibration to the air more efficiently.
Deep inside the
Soundbox
It is for this reason that acoustic guitars have a hollow body. The body is a carefully
designed “soundbox”. The energy of the vibrating strings is transferred to the soundbox
via the saddle and the bridge over which the strings pass. The soundbox then vibrates in
sympathy with the guitar strings to create “amplified” – and therefore audible – airborne
sound waves that can be heard within a reasonable distance from the guitar. In other
words, it is the soundbox that is responsible for the guitar’s projection and volume.
A simple way of illustrating this point is to play an acoustic guitar alongside a solid body
electric guitar that you have not plugged into an amplifier. The un-amplified electric
GUITAR LEVEL 01 STUDY GUIDE
-2guitar is much quieter. Its solid body is
mainly just a mounting block for the
bridge, pickups and controls. Because it
has no soundbox, the sound waves it
generates are much weaker.
To sum up then, an acoustic guitar
amplifies the sound of the vibrating
strings acoustically – through the design
of the body or the soundbox. But the
sound of a solid body electric guitar must
be amplified electronically – through an
amplifier and loudspeaker.
The Tone of the Guitar
All well-constructed acoustic guitars
should have good projection and volume
– that is, they should make efficient use
of the initial energy applied by the
guitarist striking the strings. However, if
you listen to two well-made guitars, they
will almost certainly sound different.
This quality is referred to as the tone.
Guitar makers (known as “luthiers”)
constantly contradict one another with their
varying theories as to why an acoustic guitar
has a good or bad tone. The tonal
characteristic is determined by a number of
interacting factors, which are hard – if not
impossible to isolate.
However, the
“soundboard” (the top or front of the
soundbox) is the most important part of the
guitar with regard to tone. In fact, legend has
it that, to prove this, the nineteenth-century
Spanish luthier Torres (see Classical and
Flamenco Guitars) once made a guitar with a
body that consisted entirely of paper mache
except for the wooden soundboard. Guitarists
who played his experimental instrument were
apparently amazed by its fine tone.
Tapping the top for pitch
It can then be tuned to a
particular pitch
GUITAR LEVEL 01 STUDY GUIDE
-3Theoretically, you might think it would be possible to build a series of different guitars
with slightly varying construction details in order to establish one way or another that
which determines the tone quality. In practice, many top guitar makers do exactly this –
by changing their design slightly to produce an instrument with the sound characteristics
requested by a particular customer. However, you cannot get away from the fact that no
two pieces of wood are the same. For this reason, no two guitars have quite the same
tone; every guitar is unique to some degree.
As a general rule, all acoustic guitars should have an even gradation of tone, from the
lowest bass note right up to the high treble notes on the top strings. Neither should there
be any “dead spots” where the tone or volume changes uncharacteristically, nor there be
any over accentuated harmonic features.
It is fairly easy to determine the price differences between electric guitars because of their
obvious outward features, but the differences between acoustic guitars are less apparent.
To the novice, a $300 acoustic guitar doesn’t look much different than a $3,000 one. A
large acoustic guitar display can easily resemble a wall
full of tan gourds. Because
of this, it is important to be
able to explain the guitars’
benefits, i.e. the different
construction techniques and
woods used in order to justify
their price.
Martin OOO28EC
Sugg ret.
$3899.00
Martin OOOX1
Sugg ret.
$669.00
GUITAR LEVEL 01 STUDY GUIDE
-4-
Body materials
You will hear and use the adjectives “solid” and “laminated” quite a bit when speaking
of the woods used to build acoustic guitars. The word solid is sometimes used to describe
the wood used to construct the top, back, and or sides of the acoustic guitar. What is
meant by the word solid when used before the word “wood” or a specific type of wood
(i.e. Solid Mahogany) is that the top is one piece of wood THROUGH its thickness,
though not necessarily ACROSS the top. Laminated woods are those that use multiple
layers of wood (not necessarily the same species) bonded together to make one piece.
Historically,
acoustic
guitar
builders have used
solid woods in the
construction
of
their instruments
where tone has
been the primary
consideration.
Generally speaking
solid woods are more flexible than laminated woods and will, therefore, be more
responsive to the amount of string energy introduced. The more responsive top will move
more air. The listener hears a fuller, louder, more rich-sounding guitar. Laminated
materials are used where limiting the cost of the guitar is the primary concern. As
laminated materials are stronger, enhanced durability is a side benefit to the use of
laminated woods in guitar construction.
Wood is graded by its most important contribution to the quality of the instrument. The
top must be flexible, so the most flexible of tops will be made into the finest guitar. The
back and sides are normally graded for their stability, straight grain, and pure beauty.
Secondary grain, called figuring, such as Quilt, Flame, Birdseye, and other beautiful
anomalies in wood, are considerably rare and are, thus, more expensive. When a
manufacturer buys its wood, it is graded for these factors. Most of the wood would be
considered A grade; clear and free of knots, holes and other blemishes. Some of the wood
would be AA grade. This would be cleaner, more attractive, and possess more of the
properties that would make it a better instrument. Then, in even shorter supply, is the
stuff dreams are made of; wood that possesses all of the qualities we would want in a
guitar, wood that has great structure, character, weight and of course potential for tone.
Tops are usually made of spruce, which not only has a great sound but a grain structure
that provides high strength to elasticity. Solid tops are graded A, AA and AAA. The
AAA top is the most flexible
Sitka Spruce
Engelmann Spruce
(resonant) and the A is the
least. The A top would be
placed on a $400 guitar
where a AAA top would be
placed on a more expensive
GUITAR TECH STUDY GUIDE
-5guitar. As the price increases, the performance should improve. Sitka spruce is the most
popular. The grain line has a slight caramel color. German spruce is also popular. It
tends to be whiter in color with a less pronounced grain line. Sitka spruce is a little
warmer sounding where the German wood is brighter.
Both Adirondack and Engelmann spruces are American in origin and are offered by
some builders. Cedar, which is much darker, is often used as an
alternative to spruce. Because it is softer, it resonates more easily.
Cedar
Many finger pickers prefer cedar because it is easier to create strong
dynamics (the difference between loud and soft) without having to
play as hard. Western red cedar is commonly used today for both
steel and nylon stringed guitars, and yields a slightly warmer tone
than Sitka spruce.
The three most popular back and sides woods:
Mahogany provides a mellow, balanced sound. It is one of the least expensive of the
back and sides woods so it is usually used on entry-level
guitars or the first model in a family of guitars. The highs
are not as edgy and the bass is not as extreme as other
common woods. Finger pickers and players with a more
delicate intricate style may prefer mahogany. It allows the
player to emphasize the bass or treble through his playing
technique. Mahogany is an excellent wood for recording
because the sound is well balanced. It lacks the extreme
low-end boom of rosewood, which is difficult to record.
Adjectives used to describe the characteristic sound of mahogany are warm, sweet,
mellow and balanced.
Maple is a hard white wood that enhances the upper mid
and has great cut. Plain, or unfigured, maple is priced
between rosewood and mahogany while the flamed or
Birdseye maple can be quite expensive. The sound
benefit of this wood is brightness and clarity. Many large
body acoustics like a Gibson J-200, which generate
excessive bass, use a maple back for clarity and
definition; tightness, if you will.
Rosewood is the most expensive material and provides the most raucous sound. The
character of the wood is such that the highs, lows and
overall volume and projection are the most extreme. The
singer who really likes to belt out a tune and needs a guitar
to keep up with his voice should look at a rosewood
dreadnought.
There are several types of rosewood.
Brazilian rosewood is the type found on many of the highly
sought after vintage Martins. Some builders have managed
GUITAR LEVEL 01 STUDY GUIDE
-6to save some stock, but after it became an endangered species, the harvesting of these
trees was forbidden. Today’s production guitars primarily use Indian rosewood.
Visually, the Brazilian wood has a more intricate grain and is generally darker whereas
the Indian has a more variegated grain pattern and is a little browner in color. The debate
continues to rage as to just how much better the Brazilian sounds than the Indian. The
only thing that is clear is that the Brazilian costs considerably more.
Ovation’s synthetic bowl back (made of a patented material called
Lyrachord) has been a staple over the years for many pros. The body
acts as a reflective lens and is designed to throw the sound out of the
sound hole without a high degree of resonance. The result is a guitar that
is easily controlled in a live situation. The feedback problem associated
with acoustic guitars is reduced. Ovation offers several bowl depths
depending on your performance needs. The shallower the bowl is, the less tendency
toward feedback.
Neck Materials
The neck on most acoustics is made of mahogany. Maple
would be the next most common, again found on the Gibson
SJ200.
Gibson
SJ200
The fingerboard on most acoustics is rosewood. It works well
because it is a tone wood and because it is very durable and can
stand up to the abuse caused by
the strings rubbing against it for
countless hours. Higher priced
Rosewood
instruments may use ebony,
Ebony
which is a black wood that is
extremely hard. There is a slight
performance gain from ebony but
it is very expensive and adds a
great deal to the cost of the
instrument. Ebony is almost always the wood of choice if there
are a lot of inlays in the fingerboard. It is easier to cover
inaccuracies in the inlay with ebony than it is with rosewood.
Bridge Materials
The traditional and by far the best material for fixed bridges is ebony. It has a high
density, which aids sustain, and the transfer of vibration. Substitute woods used to good
effect include rosewood, mahogany and walnut.
GUITAR LEVEL 01 STUDY GUIDE
-7-
The Acoustic Guitar Body
You know, it’s usually not what, but how. We’ve learned a lot about the raw materials
used to build acoustic guitars. Now we’re going to find out what is done with the
materials.
Understanding the acoustic guitar can best be achieved by dividing the benefits of the
basic construction techniques into three categories, 1) all laminated body, 2) solid top
with laminated sides and back, 3) all solid body (top, sides, and back).
All Laminated body
The All-laminated guitar represents most of the entry-level product because of the
inherent economy of the material. The wood that is laminated for guitars is really an elite
type of plywood. The laminating process makes it possible to face the material with
highly figured exotic woods like rosewood or flamed sycamore at a fraction of the cost of
solid wood. Entry-level Martins are a good example of this. The DM is an American
barely over $1,000 because the
made acoustic that retails just
sides and back are laminated.
The less expensive the raw
material
is,
the
more
affordable the guitar.
The
material is created by
laminating three very thin layers
of wood together. The first
piece is positioned with the
grain facing north, the second
piece is placed so the grain runs
across the first piece at a 90degree angle and the third piece
is placed with the grain
running south. This creates not
only an extremely durable
material, but also one with
excellent resonant quality
because of its thinness.
The opposing grain placement
stabilizing quality.
Every
the grain. As the climate’s
have a tendency to warp or
moisture. Because the grain
opposing each other, it creates
which actually stabilizes the
that the more costly solid
more susceptible to warping
laminated counterparts. The
durable materials are obvious
likely to physically abuse the
gives the material a selfpiece of wood has a pattern to
humidity changes, the wood will
bow as it takes on or gives off
patterns of the laminates are
an equal “push-pull” force,
material. The irony of this is
wood instruments will be much
and
cracking
than
their
benefits of these incredibly
for beginners who are more
guitar.
Most important is how the sound of an all laminated guitar compares with an instrument
with a solid top. You will soon learn that a solid top will resonate more freely, making a
louder and fuller sounding guitar. The reason is simply flexibility. The opposing grain
and layers of glue make the laminated top stiffer. This reduces the volume and the bass
response. The result is a guitar that sounds brighter or more trebly with less volume.
This comparison is made with two guitars identical in every respect except the top. Even
GUITAR LEVEL 01 STUDY GUIDE
-8when comparing two identical guitars, you will notice some variation. This is because
wood is a natural material, lacking the uniformity of man-made materials. Laminated
guitars, because of their layered process, do have greater degree of sound uniformity. It
is possible to create an amazingly good sounding laminated guitar with quality material
and construction. There are very expensive jazz guitars like the Gibson ES-175 that
utilizes laminated wood. The visible type of wood used for the front and back of a
laminated guitar is usually that which is described. The inside piece of wood might be
another type. For example, the laminated spruce top guitar may use mahogany
underneath. Using the same wood underneath will produce superior results.
.
Solid Top Body
Martin DM
Solid Top
The existence of the Solid-Top guitar stems from every guitar
manufacturers knowledge that the top is by far the most important
part of the guitar with regard to tone and volume. The strings
exert about 170 pounds of pull on the top and when they vibrate,
the energy is transferred to the top via the bridge. The movement
of the top is in fact an air pump. The more radical the movement
of the top, the louder and fuller the sound becomes. When a
laminated top is replaced with a solid top, there is a major
improvement in performance resulting in more volume,
projection, and better tone. Solid wood will also improve in
performance as it ages. It is important to note that this
improvement is not because the instrument is older but because
the years of playing have loosened up the grain structure making
the instrument resonate more freely. The sides and back of the
solid top guitar remain laminated to save money.
All Solid Body
In the manufacture of an All-Solid acoustic guitar, tone and
volume are of the utmost priority. Because the backs and sides of
the acoustic guitar are part of the sound-box they are vibrating and
moving air along with the top, just to a lesser degree. Going from
solid backs and sides to laminated backs and sides is going from a
responsive construction to a less responsive construction. With
solid tone-wood you hear the wood’s full tonal spectrum
uncompromised by other materials. The discernible difference in
tone and harmonic content can be quite dramatic depending on the
quality and type of wood used. This also gives each guitar its own
‘signature sound’. An all solid guitar can retail from $1,000 and
up. When in the $5,000 range, the sound quality should be quite
extraordinary. An instrument built with an All-Solid construction
has much more potential for the instrumental uniqueness which is
the hallmark of an individual builder. It’s important to think of
the All-Solid construction as the bench mark; that against which
the other construction types are compared. There was a time when all acoustic guitars
Martin D16
All Solid
GUITAR LEVEL 01 STUDY GUIDE
-9were made this way. It was only a super increase in popularity of the guitar that drove up
the prices of All-Solid guitars high enough to leave a vacuum in the low price points
spurring the development of cost effective alternatives (laminated guitars).
The Top
Contrary to expectation, not all flattop-steel-string acoustic guitars actually have flat tops.
The soundboard is in fact often given a slight curve or “arch”. The reasons for this are as
follows. From a structural point of view, giving the soundboard and the back of the
guitar body a slight curve will make it stronger and help prevent cracking and distortion
of shape.
Such
soundboards are also
less likely to be
affected by extreme
changes of humidity
and
temperature.
Some guitar makers
also claim that a
curved
soundboard
gives the instrument a
better tone; this is, of
course, a subjective
judgment.
Fingerplates
Also known as “scratch plates” or “pickguards”, fingerplates have no function other than
to protect the soundboard from the scratching and wear caused by the guitarist’s
plectrums and fingerpick. Classical guitars do not have fingerplates but they are almost
always added to steel-string guitars.
Gibson
Everly
Brothers
The traditional material used for Fingerplates had always
been tortoiseshell but more than adequate man-made
imitations are readily available nowadays. Fingerplates are
sometimes decorated with engraving and inlays.
The fingerplate is really a compromise. Ideally the
soundboard
should be as
Two piece
flexible
as
back on a
possible
and
Martin D50
should be allowed to vibrate freely. This is
why fingerplates should be moderately thin
and make from a material that will not
inhibit the sound of the instrument. Of
course, some famous guitars have very large,
very thick fingerplates (Gibson “Everly
Brothers”) the amount by which this affects
the tone is open to debate.
The Back
The standard two-piece back is made by
butting the two pieces of timber together
with a glued joint. This joint is usually
GUITAR LEVEL 01 STUDY GUIDE
- 10 strengthened on the inside surface with a
fairly flat-section strip of hardwood, which
should have its grain set at right angles to that
of the back. The back is then strutted or
braced in a similar way to the soundboard,
and it is quite often curved in the same way
by making the struts to a slightly convex
shape. Sometimes a decorative inlay is set
along the joint in the center of the back.
Clamping glued
two piece backs
The Sides
The sides, or ribs, are made up of two pieces
of hardwood, which meet at the point where
the neck will be fitted onto the soundbox (the
top block) and again at the opposite point at
the tail end of the soundbox (the bottom
block). The neck and its heel will eventually
cover the joint at the top block. The joint at
the bottom block is dealt with in a variety of
ways. Some makers set a wedge-shaped
piece of wood at this point. Others decorate
or disguise the joint using inlays. Some
lower-priced instruments simply have a butt joint.
The top block is usually far
more substantial than the
bottom block as it has to
accommodate the female
slot of the dovetail joint by
which the neck is attached
to the body.
Honduras
mahogany is popular choice
for both blocks but the choice
Top blocks with
of wood varies. The top
dovetails cut into
them
block is traditionally made
from one solid piece of
timber, but many makers prefer to use a laminated
block that will give far more strength.
Decorative bottom
block joint on a
Martin D50
GUITAR LEVEL 01 STUDY GUIDE
- 11 -
The most common method of forming and assembling the body of an acoustic guitar
involves the use of a mold or former. When the ribs have been cut to shape and prepared,
they have to be formed or shaped into the curves, which follow the shape of the body. To
achieve this, the wood is first soaked in water until it becomes pliable. The ribs are then
bent into shape around a metal bending pipe that is heated so that, as the ribs are placed
against it, the water
turns to steam and the
dried-out wood retains
the shape it is given.
After shaping, it is
common practice to
clamp the ribs in the
mold overnight or at
the least for a few
hours to prevent them
from losing the shape
they have been given.
This is the point at
Ren Ferguson and
which
the
guitar
friend pull ribs
soundbox
really
starts
from a mold at
to take shape. With
Gibson, Montana
the ribs in position in
the mold, the top and bottom blocks are glued and clamped into place thus joining the
two ribs and forming the outline shape of the guitar soundbox. The “linings” are then
glued and clamped to the ribs so that finally the soundboard and back can also be glued
and clamped in place.
Linings are continuous strips of wood employed solely for the purpose of making good
joints inside the soundbox – between the soundboard, ribs and back. Without them, the
thickness of the soundboard ribs and back is not sufficient to allow reasonable joints to be
made. To aid the bending of the linings and so that they match the shape formed by the
ribs, they are “kerfed”. This means that a saw cut is made through the bulk of the lining
every ¼’ (6mm) or ½ in (12.55mm) along its length.
Two types of
kerfed lining
Small wedge-shaped
pieces of wood are an
alternative
to
continuous
linings.
They are fixed in
exactly the same way
–
by
clamping.
Kerfing in place
Whichever method is
used, the wood is
tapered or rounded to do away with superfluous timber. By
doing this the maker can keep the weight of the linings down
GUITAR LEVEL 01 STUDY GUIDE
- 12 and also ensure that their shape will have a minimal effect on the internal dimensions of
the soundbox.
Top-class hand-made instruments might be made with pine or cedar linings joining the
soundboard and the ribs and hardwood linings joining the ribs and back. Some American
makers prefer to use basswood for linings. Mass produced guitars are sometimes made
with linings which are in fact lamination of two or three strips of wood.
Edging
Edging is traditionally made from thin veneers or strips of hardwood laminated together.
First-class instrument makers still employ rosewood, maple and other hardwoods for the
edging on the guitars they make but plastic edging is by far the most widely used material
on the majority of guitars being made today.
The edging pattern is sometimes repeated at the bottom of the instrument to camouflage
the joint there between the ribs. The same pattern used in the edging – or a variation of it
is sometimes repeated along the edges of the neck and on the head of the instrument.
Some makers choose to elaborate on edgings by using such materials as mother of pearl;
they may actually put more effort into edging and decoration than others put into making
an entire instrument. This is of course, all a matter of personal taste. Other makers feel
that decoration should be kept to a minimum for aesthetic and tonal reasons.
Book matching is another important technique used to prepare
the wood of a solid top guitar. Looking at the front or back of
an instrument with a highly figured grain pattern, you will
notice a seam running exactly down the middle of the top with
identical grain patterns on each side of it. This is achieved by
Book matched
Cedar
sawing a piece of wood
in half and then opening
it up like a book. For
esthetic beauty or visual
GUITAR LEVEL 01 STUDY GUIDE
- 13 symmetry, it is essential to use this technique. It also assures that movement of the wood
caused by climatic changes will be balanced and symmetrical as well. Each unique piece
of wood has varying areas of density that will react differently to climatic changes.
These changes will cause the wood to either absorb moisture or give if off. When bookmatched, the identical sides of the top will react exactly the same to climatic changes,
hence preventing cracking and splitting. Failure to do this will cause the wood to work
against itself. That is the perfect scenario for splitting or cracking. You will notice that
even laminated guitars have the visible laminates on the top, sides, and back bookmatched.
Looking at the grain line at the edge of the sound hole, you will notice it is standing at a
90-degree angle to the top surface of the guitar. This is because each grain line acts as a
tiny “I beam” which provides great structural strength to the top. This 90-degree
positioning is achieved by a process called “quarter sawing”. This process positions the
tree so that the grain of the lumber is
vertical. The wider the grain spacing,
the bassier sounding the guitar. Wider
grain spacing means more flexibility that
means a louder, fuller sound. Many
players insist on a close grain for
Plain sawn can
cosmetic reasons. Some builders will
also be called slab
tune the top to different notes such as C
or flat sawn
or D, giving each guitar a distinct sound.
The top can also be made thinner or graduated at the edges by gluing edges adjacent to
sides for added power and bass response.
GUITAR LEVEL 01 STUDY GUIDE
- 14 -
Struts and Braces
All guitar soundboards are strengthened by a pattern of
struts and braces on the inside of the soundbox. However,
the designs for internal strutting and bracing vary
considerably. Ideally, a soundboard should vibrate in a
uniform way, with the strutting giving only structural
support and strength. The strutting pattern can radically
affect the sound of a guitar.
Struts or braces
The large X bracing found
on the bottom of the
soundboard is the standard
brace pattern for steel string
acoustics. These two large
braces are responsible for
keeping the top flat and true.
Shaving arches or hollows in
X Braces
the braces is a technique
called scalloping.
This
improves the flexibility of the braces and, more importantly,
reduces the inertial mass of the top allowing it to resonate more
freely. The result is a louder bassier, more responsive guitar. The
technique, designed by Martin originally, is in common use these days on better guitars
and even some laminated top guitars.
The Bridge
The vibrations or energy from the guitar strings are transmitted to the soundboard
through the saddle and bridge. The bridge must be efficient in the transmission of the
energy and strong in both its construction, and of the way it is attached to the soundboard.
There are two basic types of bridges. One is the floating bridge (usually used on f-hole
guitars) and the other is the fixed bridge (generally the type fitted to flattops).
A floating bridge is so-called because it is not actually
fixed to the soundboard but is held in place simply by
the tension of the strings, which pass over it. The
strings are secured to a fixed tailpiece. Floating
bridges can therefore be moved backwards and
forwards to correct the intonation if necessary.
Fixed
bridges are glued to the top of the
Floating Bridges
soundboard and cannot be moved.
There is usually no separate tailpiece;
instead, the strings are anchored directly
Fixed bridge
GUITAR LEVEL 01 STUDY GUIDE
- 15 to the bridge. The joint between the bridge and the soundboard must be first class. Both
surfaces are usually “toothed” or “keyed” meaning that the surfaces of the wood are
roughened in order to make the joint stronger.
To give extra strength to the bridge area of the soundboard, a piece of wood, called a
bridge pad or bridge plate is usually fitted to the underside directly beneath the bridge.
Some makers also glue a thin veneer of wood to the underside of the soundboard around
the soundhole/rosette area to add some strength.
The traditional and by far the best
material for fixed bridges is
ebony. It has a high density,
which aids sustain, and the
transfer of vibration. Substitute
woods used to good effect include
rosewood, mahogany and walnut.
On flattop guitars the strings are
usually secured to a fixed bridge
by bridge pins. These hold the
ends of the strings in place in the
bridge pinholes. They are tapered
Bridge pad or
plate
so that when they are inserted in
the holes in the bridge a snug fit is
achieved without the pins becoming too tight. There should be a small groove in the
bridge at the point where each string comes out of the bridge pinhole and turns at a sharp
angle towards the saddle.
The slotted or pinless bridge is a fairly recent innovation and differs
from a standard fixed bridge only in the way the strings are attached.
Slots through which the strings pass through replace the bridge pins
and holes. The slots are large enough to allow the strings to pass
Bridge pins
through them but small enough to catch the metal “barrels” or “endpieces” attached to the ends of the strings.
Pinless
bridge
GUITAR LEVEL 01 STUDY GUIDE
- 16 -
The Neck
.
Acoustic guitar
necks are
These necks are
being carved from
traditionally
1 solid piece of
entirely made
Mahogany
each
of one solid
piece of wood.
You will now
see acoustic
guitar necks
that are pieced
together as
well. Necks can
be pieced
longitudinally
or horizontally.
Necks that are
A 3 piece
pieced
laminated
longitudinally are called laminated necks.
neck
There can be a couple different reasons a
builder may chose to laminate a neck. Just like laminating
guitar tops, laminating necks saves money. On the flip side, it
also makes the neck stronger and, more importantly, stiffer.
Normally, piecing a neck together horizontally (the
headstock being a separate piece of wood attached to the end
of neck) is done for cost saving reasons exclusively. The
positive spin is that is a “greener” way to build guitars
because this technique saves wood. Taylor guitars use a
pieced together neck to ease the effects of their guitar
The scarf joint explained
building on the environment. A close examination of the
headstock/neck joint on a Taylor reveals a different method of
headstock attachment than budget guitars. While the budget acoustics use a simple
carpentry joint called a scarf joint, Taylor employs a finger joint. This joint is actually
stronger than a one piece neck at the normally fragile thin spot on the neck behind the
nut.
The typical neck length of guitars built through the early part of this century was 12 frets,
nut to the neck/body joint. A great example of a 12 fretter is the Martin D-28S. People
just didn’t need to play, as high up on the neck back then. There was also a structural
benefit. The shorter neck exposure didn’t require the adjustable truss rod. Classical or
nylon string guitars are 12 frets to the body. From a performance standpoint there are
several advantages. First, the neck is shorter but the string length is the same as the 14fret neck. This means that the bridge is set farther back into the lower bout or the wider
GUITAR LEVEL 01 STUDY GUIDE
- 17 -
12 fret Martin
14 fret Martin
Measuring the scale
length; the length of
the vibrating string
more flexible part of the guitar
top. By placing the bridge in a
more flexible part of the top, the
guitar becomes louder with greater
projection. In the case of the
Martin D-28s, the top is also
longer than the regular shaped
dreadnought and that adds to the
effect. Soon after, players came to
love the 14 fret to the body style
most common today. Secondly,
the 12 fret instruments usually
have a slotted headstock. This
type of stringing setup makes it
more difficult to restring but it
increases the angle of the string
over the nut, which increases the
bearing pressure making the string
performance better. Since most
finger pickers play more lightly,
they enjoy the performance of the
slotted headstock. Scale length is
the total length of the vibrating
string. The longer the scale length
is, the
greater the
string
tension.
The plus
side of
having
greater
Slotted
string
headstock
tension is
that it puts more pull on the top,
creating a louder guitar with better
clarity. The down side is it may
feel a bit more difficult to play,
especially if you like to bend those
strings. The martin OM
instruments use a longer scale than
the 000 models. As a result, the
OM’s generate more volume or
punch than the 000’s. Taylor’s use
a 25.5” scale length.
GUITAR LEVEL 01 STUDY GUIDE
- 18 The neck shape is usually rounded or elliptical. Some companies offer what has been
called a “low profile” neck shape which makes the neck shallower from the front of the
fingerboard to the back of the neck. This can make the neck feel more comfortable.
Taylor sets the pace for those players who prefer a thinner neck profile from front to
back. Martin and Guild tend to have a more full or “traditional” thickness, though
Martin, since the mid 1990’s, did choose to make its neck with a “lower profile” than
before to follow the current trend.
All fingerboards are narrower at the nut (where the strings are closer together) than they
are at the other end. But the actual width varies quite a bit from guitar to guitar.
The neck width will vary depending on the playing requirements. A standard neck is
usually 1 & 5/8ths or as with Martin 1 & 11/16ths wide at the nut. The wider the
fingerboard is, the wider the string spacing. Many finger style players prefer a wider
neck. The wider neck allows for greater accuracy if your style is more intricate or
demanding. The dimensions on the wider necks are usually 1 & 3/4, 1 & 13/16ths and 1
& 7/8ths at the nut.
Fingerboards on most acoustics are made from Rosewood. More expensive acoustics may
use the satiny black wood Ebony (by the way, on steel stringed acoustics the fingerboard
wood and bridge wood are usually the same). Be aware that some makers will dye
Rosewood black to make it look like ebony.
A series of saw cuts are made in the fingerboard to accept the frets. The frets are “T”
shaped in section. The top of the fret is rounded so there are no sharp edges to damage
the fingers or strings. The upright stem of the “T” is serrated which means it has a
roughened edge
that grips the sides
of the slot in the
fingerboard when
it has been gently
Looking at the
hammered or
fretboard from the
pressed into place.
edge; note the “T”
shaped fret end
Most steel-string
guitars also have
fret markers inlaid into the fingerboard. They
are simply a visual aid to help the guitarist
identify fingering positions. Classical and
Flamenco guitar usually have flat
fingerboards but many steel-string guitars
have fingerboards with a slightly convex
curve to the fretted playing surface.
A master builder pressing
frets into a fingerboard at
Gibson, Montana
GUITAR LEVEL 01 STUDY GUIDE
- 19 -
More about the neck
If the inlays in the fingerboard, the sound-hole rosette and the body are extremely
colorful, they are probably abalone shell. The less outrageous color inlay is called
mother of pearl. Less expensive guitars will use a synthetic abalone-looking plastic
around the body.
For a more
traditional look, the body can be
bound with a herringbone design,
which is a treatment that Martin
Guitars developed before World War
II. The variety is endless.
Fret size also relates to the type of
playing style. A traditional player or
finger picker will usually prefer a
smaller fret. Finger style or folk
Abalone
players are not as big on vibrato and
fingerboard inlay
so the larger fret is not a benefit.
Also, the higher the fret the deeper is
the more it cuts into the meat of your finger. Acoustics that are more geared towards the
rock player will have a larger fret. Ovation is the perfect example.
An obvious difference
between the neck on an
This heel is not
pieced together.
inexpensive guitar and a
“Look mom, no
premium guitar is at the
extraneous joints!”
heel.
Less
expensive
guitars will have a
laminated heel. The reason
for this is that to make the
neck out of one piece of
wood takes a very thick
piece of lumber. There is a
considerable cost saving
achieved by laminating the
heel.
However,
the
motivation behind piecing
together the heel can be different. Our friends at Taylor piece the heel together as not to
waste wood in keeping with the build-it-green mentality.
Some classical guitar-makers choose to fit an additional hardwood strip set into a groove
in the neck underneath the fingerboard. This is to provide more strength against the pull
of the strings. Steel-string guitars however, have a far greater string tension so something
stronger is needed. In the early days of flattop guitar construction it became common
practice to fit a metal strip, tube, or “t” section into a similar groove running along the
length of the neck just below the fingerboard. This metal strengthening piece is called
the truss rod.
GUITAR LEVEL 01 STUDY GUIDE
- 20 -
During the 1920’s the Gibson Company came up with an adjustable truss rod, which they
fitted, to their arch-top f-hole guitars with great success. Gibson-type adjustable truss
rods – and subsequent developments of them – are fitted to the vast majority of steelstring guitars being made today.
Most people know what a truss rod is but not how it works. The obvious purpose is to
allow the player to adjust the neck if there is a bow caused by string pull or a change in
climate. It is not uncommon to adjust the neck several times a year. The adjustment nut
can be accessed inside the sound hole or on the face of the headstock. There are two
basic styles most commonly used.
Cutaway view of
the entire truss rod
The standard style uses a steel rod anchored at the
heel and threaded with a nut at the other nut. The
rod is laid into the neck in a U-shaped channel that
runs from the heel to the nut. The fingerboard is laid
over this channel after the center or low part of the
channel is filled in with a blank. Some companies
have a rod that is encased in an aluminum sleeve.
When the nut is turned clockwise, the rod is literally
pulled through the nut. Imagine a rope that is
sagging in the middle. When the one end is pulled,
the rope becomes straighter. This has the effect of
pulling the headstock end of the fingerboard back. If
the neck is bowed back, simply turning the nut
counter clockwise (loosening it) will allow the string
tension to pull relief into the neck. During this
process, the rod does not turn.
The headstock end
of the truss rod
Dual action truss
rod
The heel end
The second style is called a
dual action truss rod. In
this case, a rod is laid into
the neck in the same
fashion except there is a nut
at each end, one with
reversed threading. To make an adjustment, the rod itself is turned which cause the nuts
at each end of the neck to move outward or inward. This type of rod is more sensitive
and requires less adjustment to make the needed compensation.
GUITAR LEVEL 01 STUDY GUIDE
- 21 The tuning heads or machine heads increase or reduce the tension exerted on each string,
thus raising or lowering its pitch and allowing the guitar to be correctly tuned. The
tuning heads generally fitted to flat-top-steel-string acoustic guitars consist of a capstan, a
worm gear and a tuning button on a metal shaft, all mounted on a metal fixing plate.
Some tuning heads have individual fixing plates; which means that you can replace single
tuning head should one develop a fault. Others consist of two pairs of three tuning heads,
which are mounted on a pair of fixing plates so that each group of three tuning heads is at
a set distance apart.
Worm
gear
Metal
bushing
Metal
shaft
Tuner
button
Fixing
plate
Capstan
Any quality-tuning head should have a metal bushing inserted into the hole in the
headstock through which the capstan passes. This prevents undue wear and stops the
capstan from binding against the wood of the headstock. Some kind of gearing is
necessary to facilitate fine-tuning to allow the tuning button to be turned with relative
ease and to prevent the string tension from turning the capstan. Gear ratios can differ
considerably, but anything in the region of 10:1 will make re-stringing and tuning
relatively easy. Top-line manufacturers of tuning heads (such as Grover) have the
gearing section totally enclosed to allow permanent lubrication.
Individual sealed gear
tuning machines
3 on a side tuning
machines
GUITAR LEVEL 01 STUDY GUIDE
- 22 -
Neck Joint
One crucial component of acoustic guitar design, construction and sound quality is the
mean by which the neck and body are attached.
A dovetail joint is the most common method used for fitting the neck of a flat-top-steelstring guitar to the body of the instrument. The end of the neck and heel are shaped into
the male part of the dovetail joint. The recess or female slot is cut out of the top block.
The neck is then inserted and the joint is glued.
The dovetail joint is believed to produce the strongest connection between the neck and
body resulting in superior performance. The attack, sustain, and power should be
excellent. The dovetail joint used on most guitars actually is a compound dovetail. That
means it’s dovetailed in two directions. The mortise & tenon (a sort of “tongue-in
groove”) is dovetail-shaped, so it will slide in, and it’s also wedge-shaped, so that when it
slides in, it will eventually hit bottom. The surfaces are glued, and the result is an
extremely strong wood joint. Should the need arise for major neck repair, it’s quite
expensive and requires an expert to remove the neck.
Bolt-on or Removable Neck Construction
In the 1960’s, several companies launched an illfated effort to apply the solid body bolt-on neck
design to acoustic guitars. A huge neck block
was installed in the body and then a pocket was
cut to accommodate a Stratocaster-type neck,
which was screwed on with a plate like that found
on a Stratocaster. Unfortunately, the body
couldn’t withstand normal string tension. One
company attempted to stabilize the joint with a
metal pipe that went from the neck block to the
endpin. Not surprisingly, the project was not a
success. Conversely, one of the guitar industry’s
GUITAR LEVEL 01 STUDY GUIDE
- 23 recent success stories is that of the Taylor bolt-on neck design. The neck heel and block
are sanded perfectly smooth, and then bolted together. The result is an easy-to-remove
neck, which makes performing extremely slight adjustments quick and easy.
Mortise and Tenon Construction
Another fairly
recent approach is a
non-dovetailed
Mortise and Tenon
glued-in neck joint.
Tenon
Mortise
Martin, for example,
has designed an
ingenious system by
which an extended
neck block is
grooved to butt
directly under the
fret board. This
added support
prevents neck dips and humps. A threaded bold holds the components in place while the
wood dries. This is a fast, consistent production method, which retains many of the
compound dovetail’s sound properties.
GUITAR LEVEL 01 STUDY GUIDE
- 24 -
Body styles
The Dreadnaught is the most popular shape and has until
recently completely dominated the industry. Martin
created the shape in 1916 for an OEM account and put it
into Martin production in 1935. The rectangular shape
with the soft waist creates a very large soundboard
resulting in great power and projection. The tone is
strong across the entire spectrum but it is weighted in
the low midrange. Because this style so completely
dominated the industry, it is hard to associate it with
specific style of music. One thing is certain. No selfrespecting bluegrass player could consider his life
complete without a Martin D-28 in his arsenal. The
great power produced by this body makes it possible to
compete with the volume of banjos and the cut of a
mandolin. Players who need more clarity may prefer a
smaller body.
Concert and Auditorium models are examples of smaller
bodied acoustic guitar styles which produce an evenly
Martin D28
The
balanced sound.
When compared with larger bodied
Dreadnaught
instruments, there is a lack of bass and volume. However,
many great players consider the trade off between the power of
the large body and the definition of the small body well worth it. The smaller body also
lets the player have greater control over tone. Bass or treble can be articulated by the
player’s technique.
Taylor Body Styles
Dreadnaught
Grand
auditorium
Concert
Jumbo
The Gibson J-200 and Taylor jumbos are examples of large body jumbos. This shape is
characterized by rounded upper and lower bouts with a tight waist. These powerhouse
guitars generate powerful bass and a respectable treble response. The midrange is not as
pronounced. These guitars are best classified as rhythm guitars because of the tight lowend punch. Elvis, John Denver, Emmylou Harris and countless country artists prefer this
style.
GUITAR LEVEL 01 STUDY GUIDE
- 25 -
Mini Jumbos are the same shapes in a smaller package. The performance characteristics
are the same with less volume due to the smaller body. As the body becomes smaller,
there is an improvement in clarity due to a more moderate bass response. Smaller players
will also appreciate the reduced size. This Gibson J-185 is a great example of this shape.
Gibson J185
Gibson J180
GUITAR LEVEL 01 STUDY GUIDE
- 26 -
Amplifying the Acoustic Guitar
Acoustic guitars can be amplified
with a vibration sensitive piezo
electric pickup mounted under the
saddle, a magnetic pickup in the
sound hole, or a miniature
condenser microphone mounted
inside the body. These devices can
be used separately or in
combination of two or all three.
Plugged in and
turned up
Saddle Pickup
The original piezo electric saddle pickup is still the most popular style pickup. It is
designed to reproduce the actual sound of the resonating body making it very natural
sounding. This device places six or seven piezo electric crystals in a channel under the
bridge saddle. When the string is struck it makes the crystal vibrate which creates a
voltage that can be amplified. The latest advance in the saddle pickup is the use of a copolymer strip that is sensitive along the entire length of the pickup instead of six separate
crystals, one under each string. The result is a more even response from each string,
easier set-up, more bass response, and less feedback.
These
devises
function
best
with an onboard
pre
amp,
however,
in
certain cases if
your
sound
Ovation OP-Pro preamp
system has a strong
A saddle pickup
enough pre amp you
may be able to avoid one. Takamine is an example of an acoustic electric with an
elaborate onboard pre amp and control system. Mounting the pickup under the saddle
gives you the greatest control and it also places the pickup in the harshest sounding part
of the guitar. A quality pre amp and EQ system will allow the player to achieve the
warm natural sound expected from an acoustic guitar. Some high-end builders believe
the mounting process and the weight of the unit negatively affect the performance and
structural integrity of the guitar. Most of the onboard control systems mount into
laminated sides that are less likely to crack than solid sides.
GUITAR LEVEL 01 STUDY GUIDE
- 27 -
Magnetic Pickup
The magnetic soundhole pickup is the same as
the pickup on a standard electric guitar. Most are
engineered to accentuate the natural frequencies and
qualities of the acoustic guitar. This pickup works off
the vibration of the strings rather than the vibration of
the body, so it is a little more electric sounding than the
piezo pickup. The construction materials used in the
body do affect the tone and performance, however.
This type of pickup is the best at controlling feedback
and is the easiest to install. These pickups come in
single coil like a Fender Stratocaster and double coil
like the Gibson Les Paul. The single coil will give a brighter clearer sound while the
double coil will provide a bassier fuller sound.
Microphone
Special condenser microphones are now available to
mount inside the body of the guitar. This can work
out very well but keep in mind that there is more
potential for feedback.
(Feedback is the
uncontrolled howling caused when the acoustic body
reacts to the volume and frequencies produced by the
sound system.) This system is usually used in
conjunction with a piezo or a magnetic pick to make
the sound more natural. The challenge is to find the
best place in the guitar to mount the microphone for
optimum tone and minimum feedback.
Soundbox microphone
The Case
The best reason for a good case has more to
do with protecting the guitar from the
climate than from physical abuse. Rapid
changes in humidity and temperature are
much more damaging than an occasional
scratch. Even at home, it is a great idea to
keep a quality instrument in a case.
GUITAR LEVEL 01 STUDY GUIDE
- 28 -
The Finish
The finish also has a significant effect on the sound of the guitar. Entry level guitars have
a synthetic polyurethane finish for several reasons. The finish can be the most expensive
part of the guitar because of the amount of time and effort that goes into producing a
quality finish. Polyurethane allows a builder to save time by applying a thicker finish
that reduces the number of coats a typical lacquer finish
requires and by using high power buffers that would
destroy a lacquer finish. Also, a poly finish dries more
quickly, reducing the overall time it takes to make a guitar.
The downside is that the thicker finish will, in effect, stifle the ability of the guitar to
resonate. The guitar will not be as loud or as full sounding. It is almost impossible to
spot finish a chip or scratch on a guitar finished in poly. On the plus side a poly finish
reduces the cost significantly and stands up too much greater abuse. The abuse can take
the form of physical roughness as well as severe temperature shock that might cause a
lacquer finish to check or crack. Think of the beautiful vintage guitars with hundreds of
lacquer checks. Builders
like Taylor are finding ways
to produce excellent
synthetic finishes. Their
pioneering use of ultraviolet (U.V.) curing systems
has reduced curing time
from weeks to only seconds.
Pros: Inexpensive, tough as
a boot, easy to apply, stable,
environment-friendly, and
VERY shiny.
Cons: If used too thickly,
it’s like laminating a guitar.
Repairs may be difficult
Checked Lacquer
High priced guitars usually use a lacquer finish. Lacquer makes it easier to spot finish a
repair. Some builders are finding that environmental restrictions are making it more and
more difficult to use lacquer. This finish appears on nearly all guitars dating from the
60’s and previously. Lacquer is very volatile. That is, in its liquid form it evaporates in a
hurry. It’s applied in several thin coats, and is a good-looking, good-sounding, “old
world craftsmanship” finishing technique. It is still used by Gibson, Martin, and on some
reissue Fenders electrics.
Pros: Thin, breathes well, resonates well, easy to spot-repair.
Cons: Expensive, labor-intensive, may be prone to sinking or clouding if improperly
applied or cared for, and is very rude to the environment.
GUITAR LEVEL 01 STUDY GUIDE
- 29 -
Scraping the finish
off the binding
Spraying Lacquer
Buffing
A French polish finish is found on really old violins,
and is still available via special order on some very
high-end classical guitars. It’s made with secretions
from the “Laq” beetle (hence the word “lacquer”) and
alcohol. It’s dabbed on and rubbed in a smidgen at a
time. It’s so thin that it leaves the grain of the wood
clearly visible. Sunburst finishes were originally
intended to suggest the appearance of old Frenchpolished violins.
Pros: Thinnest finish around. Great resonance
breathes well, easy to repair.
Cons: Extremely labor-intensive therefore expensive;
to the untrained eye, looks “homespun;” and very, very delicate. To quote Nigel Tufnell,
“You can’t even look at it.”
.
At left: Antonio
Stradivari applying
a French-polish
finish
At right: the
finished product; a
Stradivarius
GUITAR LEVEL 01 STUDY GUIDE
- 30 -
Classical and Flamenco Guitars
Don Antonio de Torres is considered “the father of the modern guitar”. He was born in
Spain in 1817 and by the age of 12 was already a carpenter and by 18 was listed in the
town directory as a master carpenter although at this time not a guitar builder. Torres
started building guitars about the same time as Christian Martin of Martin guitar fame
and in fact later in life Martin used some of Torres’ designs in his own Manufacturing.
Torres is believed to have built some 320 guitars in his lifetime. He was on a “mission”
to make a better instrument. He proved to the guitar-making world that the soundboard
was the most important part of the instrument and when braced properly that it didn’t
make a difference what material was used on the sides and back. To prove this he built a
guitar, which still exists, out of paper mache and used a top already braced of wood. The
experts were floored and this primarily led to developments in bracing techniques and
soundboard making.
He also preferred the larger shape the guitar (again today a standard), wider and thicker
fingerboards as well as his new scale length (650 MM). Some of the most famous
players of the time sought out Torres to play his instruments and he became known as the
maestro. There are supposedly many forged guitars with Torres’ label on them. It is easy
to see why every builder wanted to be associated with him. There were fewer Torres
guitars built than the Stradivarius violins of the 1700’s. Needless to say these are highly
collectable. Nearly all contemporary guitars use some of Torres’ famous designs.
GUITAR LEVEL 01 STUDY GUIDE
- 31 Ramirez is probably the most well known name in the world for
guitar building. It is a story that goes back four generations and starts
with two brothers – Manuel and Jose. Jose (1858 – 1923) started
building guitars as an apprentice at age 12 and he continued making
mostly flamenco guitars in a shop with several apprentices of his own,
including his own son Jose II. Manuel Ramirez (1864 – 1916), the
estranged brother of Jose studied in the Torres school of building and
developed in that style. In 1912 Manual repaired an instrument that
was built by Torres and actually built a guitar exactly like that one. In
the same year, Manual Ramirez had given that guitar to Andres
Segovia (built by one of his builder, Santos Hernandez). It was
believed that Manuel was the heir to the Torres throne of classical
builders (that’s right, not Jose as you might expect). Apparently,
Manuel believed in his guitars so much that he built two in the styles
of Torres, placed in two labels that he had found, and started showing
them as “unearthed Torres guitars”. The reaction of the experts was
that these were the best Torres guitars ever heard. Then he removed
the labels and his were underneath. Unfortunately, Manuel’s side of
A modern
the family did not carry on his tradition. Since that time Jose’s side
Ramirez
of the family has kept on the tradition of building, each gaining more
respect and notoriety as some of the premier builders of our time. Today, Joe Ramirez I,
II, III and of course Manuel’s guitars fetch considerable sums of money to players and
collectors alike.
Hauser
In 1924 Andres Segovia showed his Manual Ramirez
guitar to builder Hermann Hauser in the hopes he could
recreate his 1912 guitar; it took Hauser 13 years (1937) to
produce something similar (actually better) and from that
point in time Segovia played the Hauser. This guitar
became his number one guitar and set the Hauser name in
classical guitar making history under the original designs
of the Manuel Ramirez guitar, which was built of the
Torres style. Many people consider Hauser the finest
builder in the world, while others believe that they are the
best outside of Spain. Hermann Hauser II was every bit as
well respected a builder as his father and like the Ramirez
family; Hermann Hauser III is building some of the finest
Herman Hauser
classical guitars in the world today. Also, like Ramirez,
Hauser I and II’s fetch incredible amounts of money in the vintage market. (A Hauser
trademark is a well played in guitar, Hermann actually has local students come to his
factory and play a new guitar for 8 hours a day for 30 days. He builds 12 –15 guitars a
year).
GUITAR LEVEL 01 STUDY GUIDE
- 32 You will note from looking at these Concert guitars that they do all seem similar from a
distance. It is only when you get close do you notice the subtle differences. The
headstock, rosette, and label are like a builder’s signature. The neck joints and headstock
joints are other telltale signs of a quality guitar maker. There are so many names in the
history of guitar making in Spain during the 1800’s and 1900’s that you should know. As
you may have already noticed, they either worked for a Ramirez or studied in the style of
Torres. In a strange way it seems that they are all related in some way or another. Just a
few of the builders of note are:
Enrique Garcia (1868 – 1922) apprentice to Manuel Ramirez.
Robert Bouchet (1898 – 1986 built in France) built in the Torres style then updated
bracing.
Ignacio Fleta (1897 – 1977) built in the Torres style, then again improved bracing, make
3 guitars for Segovia in the later years, used “French Polish” shellac, also sealed and
lightly polished the inside of the back for improved treble.
Miguel Rodriquez (1888 – 1975) designed like Jose Ramirez I, almost flamenco like, and
another family dynasty like Hauser and Ramirez. His son Rafael died in 1965 and
Miguel Jr. and Sr. died recently, thus ending this dynasty
Most of this information is based on the Concert type guitars. The
Concert guitar is designed for concert performances and can be
heard at great distances with superb clarity and volume. There is a
whole other world of Student model guitars. Ramirez Student
models, as with most other Concert maker’s Student models are not
even made in they’re own factories. Sub contactors skilled in the
styles of the maker’s design typically make them. There are many
factories making guitars all over Spain, mainly in Valencia
producing guitars under many different names. Esteve and
Fernandez are names given to lines of guitars by their importer.
They could show up in different stores with different names if
another importer decides to use that same factory. This is very
common and is very similar to the factories in China and Taiwan
that produce Fender, Jackson, Ibanez and Epiphone guitars all in the
same factory.
Flamenco Guitars
A Cordoba 50R
student model
Flamenco is the music of the gypsy people of Andalusia, the region
of Spain bounded by Cordoba in the north Cadiz in the south,
Almena in the east, and Huelva in the west. The origins of flamenco
are obscure although it is generally accepted to have North African
(Moorish) influences. It emerged towards the end of the eighteenth
century when it was always played as a combination of dance, song
GUITAR LEVEL 01 STUDY GUIDE
- 33 and guitar accompaniment. Later, the original form gave rise to two subsequent
developments: conte flamenco (based on different song forms) and solo flamenco guitar.
The man credited for the birth of the solo guitar form is Ramon Montoya (1880 – 1949).
Ramirez 1AF
flamenco
Flamenco has traditionally been passed from generation to generation without the aid of
musical notation. The music is frequently regarded as a loose, undisciplined form. In
fact, this is not so. It is a combination of improvisation and strict rhythmic structures of
which there are many. Flamenco is no simple man’s music. The solaria, for example,
one of the four most important structures, has a rhythm based on a twelve-beat for,
with accents on the third, sixth, eighth and tenth beats, and is played in ¾ time.
Several of the other song forms have rhythmic patterns that are considerably more
complex, and a guitarist often specializes in only one of them.
One basic difference besides the woods used on a Flamenco guitar is the string height.
Flamenco guitars typically have lower 2-5-3 mm off the fret board than the 5 mm height
found on classical guitars.
GUITAR LEVEL 01 STUDY GUIDE
- 34 Who are the customers?
a) Upscale, wealthier than other guitar customers
b) Educated, business owner, Professionals
c) Prolific in their playing and speaking about the instrument
Why are these customers different from other guitar customers?
a) They buy with their ears not their eyes and tone is more important that the brand name
b) They pay for quality they can hear
c) They expect to pay more for their instrument and don’t usually get sticker shock from
high prices
d) Concert level classical guitars are held as status symbols
There are several points you need to know about the instrument before you start talking
to customers about them. Have you tried to sell a mandolin or banjo? Do you feel
awkward? You should feel the same about classical guitars until you know the basics.
Just because thy have six strings and are similarly shaped does not mean the same rules
apply.
Think about this:
a) The strings are tied at the bridge
b) The nylon strings can take a day or more to stretch when they are new (not a few
yanks on them like on them like on your steel string or electric).
c) Classical guitars come only in two classes; Student models (made in a factory by
many people, mostly apprentices) and Concerto (Concert) models made by a Master
Builder in a workshop by hand and typically with a label that is signed by the builder.
There are exceptions to the rule that must be noted. Ramirez guitars have always been
made by a handful of builders in the Ramirez workshop by luthiers that Jose Ramirez
feels worthy to produce such an instrument. It used to be the case that Jose Ramirez
would sign the label and the builder would stamp his initials on the inside of the body and
on the neck block. Today, Jose still signs the label but there are no luthiers’ initials
inside the guitar. Another exception is Tezanos and Perez who were both builders for
Jose Ramirez III and IV. Since three people make M. Tezanos Perez guitars none of
them sign the label. Another reason they do not sign their labels is that they only make
Concert guitars and no student model instruments would be in circulation.
d) Concert guitars start at about $3,000 and can easily top $10,000 or $15,000 for a new
guitar from a famous builder.
e) Concert models are typically referred to as 1a or first quality.
f) Some builders of note that do sign and build their guitars are Hermann Hauser,
Ignacio Fleta, Rafael De Cordoba, Manuel Contreras, Greg Smallman and others.
g) Signed labels are your best tips to know you have a Concert guitar in your hands if
you’re not familiar with the maker.
h) Most great luthiers of Concert guitars produce less than 24 guitars per year. That is
something to think bout when explaining the high selling price of these fine instruments.
GUITAR LEVEL 01 STUDY GUIDE
- 35 i) There are two styles of guitar building: Torres and Ramirez (Madrid). Most guitars
follow in one of these two schools of design. Torres guitars tend to feature French
polished tops, spruce woods used for soundboards, smaller bodies, and lighter weight.
The Ramirez (Madrid Style) use cedar tops, larger body sizes, and in most case lacquer
finish.
Construction Techniques
a) Most higher end (this is a generalization) classical guitars are made using rosewood
for the back and sides and Cedar for the soundboard. Cedar topped guitars often start out
louder than equivalent spruce topped instruments. Spruce guitars go through a much
lengthier break in period where the tone mellows. A lot of makers use spruce for the
soundboard but most will let you order the guitar with either top. It can be said that the
spruce tops provide a more luscious intimate tone and the cedar can be described as
boisterous and often louder.
b) Some Concert makers (Fleta among others) actually say they can hear a difference
between Brazilian and Indian rosewood and actually prefer the Indian rosewood for its
somewhat softer sound. It’s said that the Brazilian is actually “glass-like” when taped
since it is a denser wood. As with steel string guitars, Brazilian rosewood is still the
choice of collectors because of its endangered status and rarity.
c) Many Student models use mahogany or one of the hundreds of variations of
mahogany for back and sides while still using primarily cedar for the soundboard. These
instruments range from very inexpensive to well over $1,000. Higher priced Student
guitars are made from Indian rosewood and can cost up to nearly $3,000.
d) Flamenco guitars are generally made from cypress and we are also seeing a lot more
use of sycamore. There are several reasons for this. First, it was very cheap and a
plentiful wood for the gypsies to get. Second, it is very percussive and Flamenco players
use the top of the guitar like a snare drum to keep time. The guitar is built to be “felt” as
much as heard.
e) Most classical guitars use a 650mm or approximately 23 ¾ inches. Some makers
choose different scale lengths up to 670mm (as in some Ramirez models) and down to
644mm on some older Hauser’s.
f) Generally, the bracing consists of seven struts in a fan pattern and this is attributed to
Antonio de Torres, although he also varied from this pattern from time to time. Today it
is accepted as the standard. Fan bracing is to the classical world what X bracing is to
steel string acoustics.
g) Bridges and head caps are typically rosewood.
h) Rosettes on Concert models can consist of thousands of pieces of wood to make their
design in some cases up to 15,000.
GUITAR LEVEL 01 STUDY GUIDE
- 36 -
Amplifier Study Guide
All amps share some general characteristics. Whether in “combo” form, “stack” or rack
mount configurations. Any rig must have a preamp, power amp, and speakers.
Preamp
Think of a head as a
preamp and power
amp in the same
box
Power amp
Head
Think of a combo
amp as a head and
speaker cabinet in
the same box
Speaker
Cabinet
Speaker
Cabinet
Speaker cable
Instrument cable
Combo amp
GUITAR LEVEL 01 STUDY GUIDE
- 37 Preamps, Power amps, and Loops
First things first; an amp is a sort of multiplier, which takes a weak electronic signal
generated by the pickup system of the guitar and increases it sufficiently to drive loud
speakers, possibly at hundreds of watts.
A preamp receives that incoming guitar signal, and in most cases boosts it to a “line
level”. Line level (about 1 watt) is appropriate signal strength to send to a power amp. In
the case of acoustic or bass guitar, a line level signal is often used for so-called “direct”
applications. Some bass players and acoustic electric players find that line level signal
handy for sending a signal out to the house P.A or recording console. This is the purpose
of the XLR or low impedance “out” found on many bass and acoustic amps. Electric
guitarists, and some bassists, count on their entire amp (preamp, power amp, and
speakers), not just the preamp, and the color it provides to shape their sound. Therefore,
these player’s amps are usually mic’ed and then sent to a P.A. or console.
Preamps have a major impact on tone. All the knobs on a guitar amplifier that are tone
adjustment related, except the presence knob, if there is one, is located in the preamp
section of the amplifier. Whether tube or solid-state, plain or fancy, a preamp is the
“blueprint” of a guitarist’s sound.
Effects Loops
An effects loop is a detour in the signal path. Usually located between the preamp and
the power amp, an effects loop is a comparatively noise free place to hook up guitar
gadgets after they have been tone shaped in the preamp section of the amplifier rather
than before.
The “in” and “out” on the back panel of a Marshall
DSL100
Circled in red is the effects loop section
Circled in green is the “send” which with a ¼”
instrument cable connects to the effect unit “in”
Circled in purple is the effects “return” which
connects to the effects unit “out”
GUITAR LEVEL 01 STUDY GUIDE
- 38 -
Series Effects Loops
The simplest version is a “series loop”. In a series loop, there are no controls, no
switches, knobs, or buttons; just a send (out) and a return (in). The absolute simplest
series loop is an “insert”. This is a single ¼” jack that requires a ¼” TRS to dual ¼” Y
cable but is otherwise identical to series loops with in and out jacks. The lack of any
controls means that when engaged, a series loop will always process 100% of the guitar
signal. Effects including noise gates, graphic EQ’s, and compressors work well in series
loops because all of these require the entire signal path to do their jobs.
Effect(s)
Power amp
Preamp
We have broken the amp head down into a preamp and power amp to show the signal
path in a series effects loop. The guitar signal passes through a series of events. It’s
preamplified, effected, amplified then made audible by the speakers.
Parallel Effects Loops
A more versatile (and expensive) design is a “parallel” effects loop. A parallel effects
loop allows the guitarist to blend the original unaffected preamp signal with a signal split
off from the original to the loop via a control, usually called an “effects mix” or “effects
blend” knob. Outboard digital effects truncate the fine analog signal produced by the
guitar and can otherwise change the tone so hard won by the guitarist in the first place. A
parallel loop allows the guitarist to blend his/her original signal with the effected signal
regaining what was lost. Parallel loops work great with time effects (reverb, delay, etc.)
and with digital processing.
Effect(s)
blend knob
Power amp
Effect(s)
Preamp
In the parallel effects loop an unneffected signal runs “parallel” to the effected signal. They
join at the effects blend knob located on the amp. The knob determines the ratio of effected
to uneffected signal that go on to the power amp.
GUITAR LEVEL 01 STUDY GUIDE
- 39 -
Advanced concepts in effects loops
Some high-end designs will offer, “send level”, and/or “return level” controls in addition
to a mix control. Send level and return level knobs are for troubleshooting. Guitar effects
may cause a number of different problems; drops in volume and unwanted distortion are
two common examples. Send/Return controls may compensate for such glitches. The
latest evolution in EFX loops is a tube driven system. In amps so equipped, tubes are
placed before and after the effects loop to stabilize gain. The idea here is to retain as
much tube tone as possible, even when using effects. So, look at the back panel of an
amp. A parallel, tube driven EFX loop with send and return knobs is a pretty good
indication of an amp company that sweats the details. Even if you never use the effects
loop is comforting to see engineering overkill in a rig.
Centered in this photo is the effects loop section of a Boogie Lone Star. This amp has a
sophisticated series effects loop with a send level control and a switchable hard bypass
Power Amps
A power amp receives a line level signal from the pre amp. It then boosts this signal as
much as 100 times or more then delivers a powerful signal to the speaker(s). Power amps
may be tube or solid-state. Stereo power amps are actually two separate (L&R) amps.
This is the business end of a Boogie Rectifier Stereo 2:100 power amplifier
Pure Beef
GUITAR LEVEL 01 STUDY GUIDE
- 40 -
The Physical Amplifier - Combos, Stacks & Racks
Combo amps - A combo (short for combination amplifier) is an all-in-one-box unit,
which usually includes a pre amp, power amp, and one or more speakers. Combos range
from tiny practice amps to top of the line stage rigs.
Two classic guitar combos
Marshall Model 1974X
Fender ’65 Twin Reverb
Stack systems – A stack is an amp head (usually 50-100
watts) on one or more speaker cabinets. This design helps
isolate the amp from vibration. A head on a single cabinet
is called a half stack, whereas, a head atop two separate
cabinets is a full stack. This idea is usually credited to
Jim Marshall. Jim’s first designs included an 8x12
cabinet, which was requested by the Who’s Pete
Townshend, despite Marshall’s objections. Predictability,
the cabinets were too heavy and the 4x12 cabinets
replaced them. In most cases the head (or amplifier/pre
amp) sits atop an angled or slanted 4x12, which sits on a
straight 4x12 cabinet. Angled cabinets disperse sound in a
wider pattern than do straight cabinets.
...A sweet stack. A Marshall 1959 100 watt head and
matching 1960 4X12 cabs
GUITAR LEVEL 01 STUDY GUIDE
- 41 -
Speakers and Cabinets
Speakers (or loudspeakers) are the final link in the signal chain. They receive alternating
current from the power amp and pump to and fro according to this impulse, disturbing air
molecules and delivering sound to the listener.
Open-back-cabinets -In an open-backed box a speaker will travel both forwards and
backwards freely. Consequently, there is just as much music being produced out of the
rear of the cabinet as there is in the front of it. In a small club or rehearsal room this
sound will reflect off the walls, floors, windows, and ceilings resulting in an open airy
sound, which remains fairly consistent throughout the room.
Vox AC30TBX
A classic open back combo amp
Closed-back cabinets - The first and most obvious audible difference between open- and
closed-back cabinets is the focused sound coming from the front of the closed back
cabinet. Airtight or pressurized speaker boxes limit the speaker’s ability to move
backward. This focuses the sound forward. Anyone who has ever stood in front of a stack
can attest to the extremely punchy, compressed sound these rigs put out. When the
listener moves off to either side, there is an immediate, dramatic drop in volume and
brightness. The cabinet itself has acoustic qualities; high quality birch ply versions are
renowned for their “boxy” response. The reduced travel (or excursion) of the speaker also
cuts down on wear and tear.
Ported and vented cabinets - Many bass rigs incorporate vented or ported speaker
enclosures. Although designs vary, their common goal is increased efficiency. By placing
the vents or ports of a particular size and shape in a given location, selected low
frequencies will be made more prominent. In this way designers and engineers shape the
sound of their rig.
GUITAR LEVEL 01 STUDY GUIDE
- 42 -
Selecting loudspeakers for electric guitar amps
There are at least two factors to consider when
selecting a speaker for an electric guitar amp:
Impedance and Power rating.
Impedance – a speaker is a resistor, typically
rated at 2, 4, 8, or 16 Ohms. When wired
together, as in a 4X12 cabinet, the speaker
system will be rated according to its combined
impedance. Tube amplifiers are designed to
run a specific impedance load. Expensive
damage may result if an improper impedance
load is hooked up to a tube power amp. Before
switching on a tube amp, be certain that the
amp’s impedance selector switch is set
properly, and that and unshielded speaker
cable is used to connect the speaker output
jack(s) to a speaker load of the correct Ohm
rating. Solid-state amplifiers are less prone to
equipment
damage
from
impedance
mismatching than tube gear. Nevertheless,
the minimum recommended load should be
observed. In these amps the user may be free
to select different impedance speakers based
on personal taste. Generally speaking, the
lower the impedance, the louder and bassier it
will sound.
A 25watt Celestion Greenback (above)
And
A 75watt Celestion Vintage 30 (below)
Power Rating – Speakers are usually labeled
with a maximum power rating. For a
reasonable margin of safety, a speaker
system should be rated to at least double the
RMS power of the amp it is to be coupled
with. This is not overkill. An amp’s RMS
rating is sort of an average. Occasional peaks
of greater strength may be expected (i.e., a 50
watt head needs a 100 watt cab). Again,
personal taste will play a part when selecting
a speaker based on power rating. A player
who needs a clean loud sound will be better
served by a high power rated speaker/cabinet.
Players seeking a more vintage rock tone or
who just like the sound of an overdriven
speaker will want to consider a lower power
rated speaker/cabinet.
GUITAR LEVEL 01 STUDY GUIDE
- 43 -
Distortion – The Good Kind and How to Get It
All distortion is not created equal. As the signal travels from the string to the listener
there are at least four places where distortion may deliberately be introduced.
Not distorted
Distorted!
1-Stomp Boxes- Fuzz or distortion boxes “clip” the signal before it ever gets to the
preamp. These devices are very popular and may be hooked up to any amp. Once
accustomed to a particular foot pedal, a guitarist may carry this essential component in
the string compartment of his guitar case and never leave home without it. Overdrive
pedals also create distortion but in a different way. Usually used in tandem with a tube
preamp, Overdrive pedals simply “heat up” the guitars output to the pre amp.
GUITAR LEVEL 01 STUDY GUIDE
- 44 -
2-Preamp Distortion – In any tube amp equipped with gain and master volume controls,
the gain may be turned up to create preamp distortion. The good news is that by
governing the overall volume with the master knob, it is simple to get overdrive at a
comfortable volume. The bad news is this type of sound has little touch sensitivity. A
player seeking tone with body, complexity and depth may become frustrated with the
buzzy, “all or nothing” feel of preamp distortion.
3-Power Amp Distortion- Prior to 1970, about the only way to get a tube amp to distort
was by turning up the volume. In a more modern design the same effect is dialed in by
cranking up the master. By pushing large power tubes to the limit a complex tone is
created which is very responsive to a players touch. By means of a power attenuator,
power tube clipping may be achieved at a low volume.
4-Speaker Distortion- by pushing a guitar speaker to its capacity pushing a guitar
speaker to its capacity creates a very different sort of distortion. The lower a speaker’s
power rating the more easily it will be over driven. Vintage style speakers such as those
with Alnico magnets for instance are especially well suited to this technique.
GUITAR LEVEL 01 STUDY GUIDE
- 45 -
Bass Amps
Bass Amps are expected to produce a loud, undistorted sound. To accomplish this they
differ from guitar amps in many respects.
Headroom – The distance between normal operating level and maximum operating level
in an audio system is called headroom. Bass guitarists, especially those with percussive
or slapping technique, often create unwanted distortion at the amp. By playing through a
very powerful amp at a level well below the systems limits, enough headroom is
available to avoid clipping.
Compressors and Limiters – Many bass amps feature built in compressors and limiters.
A compressor stabilizes the signal entering the amp’s power section. Peaks and valleys
are smoothed out of the audio signal. Sustain may be enhanced and the speaker will
operate more smoothly. A limiter sets the maximum threshold for a signal going to the
power amp. Unlike a compressor, a limiter should have little noticeable effect on a
player’s sound, but will protect the speaker from the excessive violence.
Crossover – separates high frequencies from low frequencies in an audio signal. In some
bass rigs, these are used to send fast, harsh peaks to a horn or tweeter. By removing these
transients from the woofers, each speaker operates more efficiently because it has fewer
frequencies to produce.
Mono Bridging – In a stereo bass amp, it may be possible to combine left and right
power amps in series to produce more power. This might require either banana or neutric
connectors or may be wired internally. NOTE-some stereo amps have a mono setting, but
are not bridged i.e. they do not use both power amps.
Bi-Amping – A bi-amp design separates incoming signal by means of a crossover, and
then sends the low frequencies to a dedicated amp and speaker component, then sends the
highs to a separate amp and speaker component.
a.
The Ampeg SVT4PRO is a great example of a bass
amp that can be run in a bi-amped configuration. On
board this amp are all the elements needed: a preamp,
a crossover and two power amps.
GUITAR LEVEL 01 STUDY GUIDE
- 46 -
Bi-amping broken down
Preamp
A bi-amp capable amp like the
SVT4PRO can be thought of as a
preamp, crossover and power
amps all in one convenient box.
Or, a biamping system can be
built from separate components
Full range line level preamp
signal
Crossover
Line level high
frequency signal
Power amp
Amplified high
frequency signal
High frequency
drivers
Line level low
frequency signal
Power amp
Amplified low
frequency signal
Low frequency
drivers
Shielded cable
Unshielded cable
GUITAR LEVEL 01 STUDY GUIDE
- 47 a.
Acoustic Guitar Amps
Until recently, a full P.A. system was required to get a
natural, realistic sound from an amplified acoustic guitar.
Electric guitar amps produce a muffled, low fidelity sound,
which is incapable of accurately reproducing the complex
sound of an acoustic guitar. Acoustic amps by means of
tweeters, pro-audio woofers, and full range EQ systems are
high fidelity amplification units that not only put good live
acoustic sound within reach of most players’ budgets, but
are also handy for use as a miniature P.A. Most feature
low impedance mic inputs, multiple channels, direct outs
for recording, and many even offer built in effects as well.
Phase switches – Phase is the effect waves have on one another. Waves “in phase”
combine and get stronger; while “out of phase” signals tend to cancel each other. Any
acoustic guitar near a loudspeaker will have some interaction; so, some builders have put
phase switches in amps and pickup systems to address this concern. At low volumes the
guitar and amp should operate “in phase” for enhanced response. At high volumes the
guitar and amp should operate “out of phase” to reduce the low pitched feedback
common onstage.
Notch filters – Notch filters can be found on acoustic amps and directly onboard the
preamps of some better acoustic-electric guitars. A notch filter is basically a preset EQ
shape resembling a “V” with a slope that gets steeper as it nears the bottom of the “V”.
The bottom of the “V” represents a dip in amplitude (volume) of that frequency of around
20db. Turning the notch filter knob moves the entire unchanged “V” shape around the
entire frequency range of the preamp from lows (lowest at full counter clockwise) to
highs (highest to full clockwise). If the guitar is feeding back, the feedback will be
drastically reduced or will disappear entirely when the point of the “V” is moved to the
frequency range that is feeding back. The player will have, in effect, turned down the
volume of that particular frequency, or frequency range, by 20db.
Modeling Technology - Modeling is a sound process that utilizes computer software to
imitate the performance of classic amps and effects, along with the ability to edit and recombine these sounds and store them in any order for live use. Modeling is not the same
as sampling. Components such as pre amp tubes, power tubes, transformers, and speakers
all have inherent sound properties. Modeling allows the designer to simulate the
performance of these components in any order. If a certain amp sounds the way it does
because the tone controls are in front of the pre amp, modeling can duplicate that. If a
particular classic amp doesn’t have a midrange control can be eliminated in the model.
Dynamic controllers make it possible for the effects to be touch sensitive. For players
who need flexibility and classic amp sounds, these amps may be perfect.
GUITAR LEVEL 01 STUDY GUIDE
- 48 -
6 Frequently Asked Questions about Amps
If an amp has two inputs, can two players jam on it?
On a modern “channel switching” amp, this works poorly, as players will have no
independent controls. Also, one guitar will almost certainly be louder than the other will.
On a two-channel amp, two guitarists may achieve satisfactory sound in a casual setting,
though this is not appropriate for recording or performance.
What are Vibrato, Tremolo, and Reverb?
Reverb is the sound of a room; the continuation of sound after the initial direct sound has
ceased. Vibrato is a regular variation in pitch (frequency). Tremolo is a regular variation
in volume (amplitude).
In what order should I use pedals?
Most players prefer distortion first then time EFX. The exception is the wah pedal which
should always be placed first in the chain.
When should I adjust my amp’s bias?
Whenever the power tubes are replaced. This will make the amp sound best and prolong
tube life.
Can I hook up a headphone amp directly to a speaker cabinet?
Not efficiently. These are little preamps with no power amp section.
Why are tube amps comparatively expensive?
Components such as tubes, tube sockets, and output (impedance matching), transformers
are not needed in solid-state amps. Some boutique amps are actually hand wired with not
printed circuit boards (PCB’s). These amps are extremely roadworthy, highly prized and
very costly.
What are “Class A” and “Class A/B” tube guitar amps?
In a Class A wired tube amp, the power tubes are always running at full capacity. In a
Class A/B amp, pairs of power tubes work in opposition like pistons. This more efficient
use of the tubes yields about 1/3 more power as well as a cleaner sound with more
headroom. Neither design is best. They sound very different and opinions vary from
player to player.
GUITAR LEVEL 01 STUDY GUIDE
- 49 What is “point to point”
hand wiring?
In a hand wired amp,
all components are
joined together with
actual
wire;
no
printed circuit boards
are used. The many
hours of skilled labor
required drive the
cost of a hand wired
amp up a great deal.
Hand wired amps
have
proven
especially roadworthy
and impervious to
vibration damage.
The chassis a hand wired Marshall
What’s the difference between speaker cables
and instrument cables?
Instrument cables are shielded to protect low
power audio signals from hum, static, and
interference. These are appropriate for hooking
up instruments and effects; however they also act
as resistors so they should never be used to hook
up a power amp to a speaker. Speaker cables are
NOT shielded and are appropriate for carrying
powerful audio signals. If used to connect
instruments and effects, the lack of shielding will
likely result in noise, hiss, hum, etc.
Shielded instrument cable
Shielded instrument cable
Unshielded speaker cable
Why do some amps have rectifier tubes and others have solid-state rectifiers?
All amps have a rectifier; some “recto’s” are tube, but most are solid-state. Prior to the
mid-1960’s all guitar amps had tube rectos. Rectifiers convert AC (wall current), into DC
(direct current) which an amp’s internal components require. In a large amp which is
cranked up all the way, tube rectifiers aren’t able to keep up with the power demand. This
power “sag” may be audible. Solid-state rectifiers are easily able to supply plenty of DC
power, which can result in a cleaner, louder, tighter, better-defined sounding amp
operating at full throttle. At low volumes there is no detectable difference in the
performance of tube vs. solid-state rectifier stage. Since the guitar’s signal never passes
through the rectifier, it is possible to have an amp with all tube signal path, yet be
equipped with a solid-state rectifier stage. It is fair to day that designers disagree over
which is best.
GUITAR LEVEL 01 STUDY GUIDE
- 50 How should I set up a half stack?
Half stacks can operate at 16, 8 or 4 Ohms depending on the impedance rating of the
cabinet being used, so set the amplifier’s impedance selector to match the impedance of
the cabinet used. There are other acceptable ways but this method is foolproof.
How should I hook up a full stack?
Two 16 Ohm cabinets result in an 8 Ohm load. Two 8 Ohm cabinets result in a 4 Ohm
load. Set the amp’s impedance switch to match the combined impedance of the cabinets
used. (8 Ohms for two 16 Ohm cabs...4 Ohms for two 8 Ohm cabs)
Loudspeaker Outputs
4ohm&8ohm parallel
jacks
16ohm
4ohm/8oh
Hooking up a half stack;
Connect the 16 Ohm speaker out on the
head to the 16 Ohm in on the cabinet with a
speaker cable.
4 ohm
8 ohm
left
16 ohm
Hooking up a whole stack;
Set the impedance selector on the head to
8 Ohms. Connect the 16 Ohm speaker ins
on each cab to one 8 Ohm out each on the
head with speaker cables.
8 ohm
right
Loudspeaker Outputs
16ohm
4 ohm
8 ohm
left
16 ohm
8 ohm
right
4ohm&8ohm parallel
4 ohm
8 ohm
left
4ohm/8oh
16 ohm
8 ohm
right
GUITAR LEVEL 01 STUDY GUIDE
- 51 -
Do different power tubes affect an amp’s tone?
Absolutely, there are about five power tubes in common use; 6V6, 6L6, El34, EL84, and
6550.
6V6 are a low power tube common to Fender Champ, Harvard,
Princeton and Deluxe amps of the 50’s and 60’s. Sweet, warm,
with a very musical distortion when pushed hard.
6L6 are a big, loud, clean, warm sounding tube. The Fender
Twin Reverb and Super Reverb amps derive much of their
familiar tone from these tubes. Variants of the 6L6 include the
softer sounding 5881, and the rare KT66 British version.
EL84 is a small tube with clangy, stinging tone. Vox AC30,
Matchless, Peavey, and Fender Blues Junior amps are equipped
with EL84’s.
EL34 is simply the sound of Marshall; powerful, with an
aggressive distortion. Although Marshall has used other power
tubes (or “valves” as the British call them) the EL34 is almost
synonymous with 50w/100w “stack” sound.
6550 is the big block Chevy of power tubes. The Ampeg SVT
Classic bass heads are powered by this large, clean, “lotsa
headroom” vacuum tube, as are some esoteric home audio
systems.
Are all pre amp tubes alike?
Yes and no. During the heyday of
tube electronics (i.e., the 1950’s and
early 60’s), manufacturers built
countless pre amp tubes with different
construction
and
sound
characteristics.
12AX7,
12AU7,
12AT7, 7028 and ECC83 pre amp
tubes from this era had meaningful
differences from on to another.
However, by the late 1990’s, only a
few tube factories remain in use.
For all practical purposes, all of the 9
pin pre amp tubes coming from a
given factory are interchangeable.
Small differences can be attributed
to two factors. First, tubes are
handmade, and are therefore
inconsistent by nature. And second,
factories differ from one another.
Russian 12AX7 tubes will differ
slightly from the Chinese version. To make a long story short; if your vintage amp calls
for a 12AU7, try to find a NOS 12AU7 that’s been in a box since Eisenhower was
president. If your modern amp calls for ECC83 pre amp tubes, any healthy 12AX7 will
work fine.
GUITAR LEVEL 01 STUDY GUIDE