Sigma Guitars
Encyclopedia
Guitar
maker Martin, based in Pennsylvania
, created a line of inexpensive guitars in 1970 to compete with the increasing number of imported guitars from Japan and elsewhere. The result was Sigma Guitars, although the Sigma line was discontinued in 2007.
The first Sigmas were typically dreadnought acoustics
, although Grand Concert Series (GCS) and classical models were also produced from the early 1970's onward. Dreadnought models DM-5 and DR-7 are the most common early Sigma guitars until the late '70s (D for dreadnought
R for rosewood
, M for mahogany
and the number denoting the grade, 7 being the top grade instrument). Construction moved from Japan (1970-83), to Korea (1984-93/94), and finally Taiwan (1993-2007).
In 1980, model lines were added to capitalize on Martin model numbers: the DM-18, DM-19, DR-28, DR-28H,
DR-35, DR-41, and DR-45. The DM-5 and DR-7, as well as other early models continued to be built during this time as well.
Sigma guitars made in Japan from 1970 through 1979 can be distinguished by a headstock
logo consisting of the single word SIGMA surmounted with the Σ symbol (the Greek letter sigma), in mother of pearl
. The sigma symbol is often described as a "sideways M." Interestingly, while playing a Sigma guitar the "sideways M" becomes "right side up" suggesting "M" for Martin.
Sigma classical guitars do not have the headstock logo, and one must rely on the inner label for identification.
Made in Japan Sigma's (1970 through the late '70s) had an inner paper label giving model and serial numbers. "Sigma Serial Numbers do not provide an indicator of the year in which a particular model was built. However, most Sigma models were offered only for a limited number of years, so that most models' construction dates can be narrowed down to a reasonable range." For example, serial numbers on the earliest DR-7s start with 4 digit numbers on through 5 digit numbers. One Sigma DR-7 owner stated "I have an old Sigma DR-7 Guitar....s/n 6860. Bought it new in 1970." Further, DR-7s with a four digit ink stamped serial number and a zero fret strongly suggests a very early build date. Later, early 70's Sigma guitar serial numbers started with 7* suggesting the 197* build date. "Sigma Martin USA" guitars built in the early 80's had serial numbers 900,001 to 902,908. Serial numbers for Sigma guitars built in Korea and Taiwan are perhaps meaningless.
In 1980 the paper labels were discontinued and the back brace was stamped. With the move of production to Korea in 1984, paper labels (of a different design) were reinstated although some early 1984 models still retained the back brace stamp.
In 1979 Sigma identified their dreadnought and grand concert guitars as "Second Generation" and the headstock design changed to utilize a gold decal stating "Sigma Guitars" with "Est. 1970" underneath, in the familiar Martin headstock decal form. High end models such as the D-10 Anniversary model have the "Second Generation" logo in mother of pearl. Guitars made in Taiwan have a different headstock label: "Sigma Guitars" on top with a miniature version of the "C.F. Martin & Co." label underneath.
The issue of whether or not Sigma guitars are solid wood or laminate
wood has been a source of controversy and confusion. This is understandable since the Martin customer service department now responds to individual inquiries stating "all" Sigma's had laminate back/sides with solid tops while Sigma catalogs from the early to late 70's list the back/side wood as solid.
To complicate matters further, in the mid-to-late 70's Sigma produced a line of guitars clearly identified by Martin, at that time, as having laminate backs and sides: model numbers starting with 52S, e.g., 52SDM-5, 52SDR-7 and 52SGCS-7. The answer to the question "Are Sigma guitars solid wood or laminate?" is best answered "That depends on the year and model." Later Sigma guitars, i.e., Second Generation, had laminate wood for the back and sides, with the exception of several models such as the D-10 Anniversary guitar.
Other Sigma instruments included mandolins, banjo
s, acoustic and electric bass
es and solid body
and hollow body
electric guitars. Some solid body electric guitar
s were made by Tokai Guitars Company, LTD.
After Sigma musical instruments were built in Japan, Korea, and Taiwan, they were sent to Martin & Co. in Nazareth, Pennsylvania
to be inspected and adjusted by Martin personnel before going to the authorized retail store for retail sale.
The DR-28 was manufactured in Japan, Korea and Taiwan while the SDR-28 appears to have been manufactured in Japan (SDR-28H, with the H signifying a herringbone inlay pattern) and Korea only, starting in early 1984. The DR-28 was of a solid Spruce top and laminated Rosewood sides and back while the SDR-28 was made with a solid Spruce top and solid Rosewood sides and back.
The DR-28 and SDR-28 are clones to the original Martin D-28 guitar and are high quality Sigma’s.
From approximately 1975 to 1984:
Sigma produced numerous "DR-*" models from the mid-70's on through 1984: DR-8; DR-9; DR-11; DR-14; DR-15; DR-28; SDR-28; DR-35; DR-41; and DR-45. During this period Sigma also produced a line of guitars with model numbers starting with 52S: 52SDM-5, 52SDR-7 and 52SGCS-7. 52S guitars had laminate backs and sides.
In the early 80's Martin imported partially assembled Sigma guitars from Japan and the assembly was completed in Nazareth, Pennsylvania. There were two models, labeled "Sigma Martin USA DR-28N and DR-35N." A Martin factory sales brochure shows the DR-28N to retail at $600.00 and the DR- 35N to retail at $650.00 The DR-35N has laminate rosewood back and sides and a solid spruce top.The DR-28Nhad a two piece back and the DR-35Nhad a three piece back. The DR-35N had additional detail on the fretboard. The original factory brochure also states components were processed and finished on the same production line as regular Martins. The Head stock reads "Sigma Martin USA" and inside the sound box is " made in USA" with Martin address etc. Some consider the DR-35N to be a prototype of the inexpensive laminate Martin Shenandoah line of guitars. Since this model had serial numbers running from 900,001 to 902,908,. it appears that nearly 3000 Sigma Martin USA guitars were produced.
In 1980 Sigma produced 100 D-10 Anniversary guitars to commemorate 10 years of Sigma production in Japan. The D-10 has solid mahogany sides and back, solid select spruce top, rosewood fingerboard with diamond and square position markers, mother of pearl
band stating "Anniversary" between the 19th and 20th fret, tortoiseshell type pickguard and binding, and close-ratio tuning machines. Regarding this guitar, Sigma enthusiast Sterling Webb stated "...equip one of these with a brass or ivory saddle, ebony bridge pins and medium strings and you can hunt down D-18s in the heaviest brush and stomp them to death...it's a very loud and impressive guitar!"
Guitar
The guitar is a plucked string instrument, usually played with fingers or a pick. The guitar consists of a body with a rigid neck to which the strings, generally six in number, are attached. Guitars are traditionally constructed of various woods and strung with animal gut or, more recently, with...
maker Martin, based in Pennsylvania
Pennsylvania
The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...
, created a line of inexpensive guitars in 1970 to compete with the increasing number of imported guitars from Japan and elsewhere. The result was Sigma Guitars, although the Sigma line was discontinued in 2007.
History
Initial construction was in Japan from 1970 through 1984.The first Sigmas were typically dreadnought acoustics
Acoustic guitar
An acoustic guitar is a guitar that uses only an acoustic sound board. The air in this cavity resonates with the vibrational modes of the string and at low frequencies, which depend on the size of the box, the chamber acts like a Helmholtz resonator, increasing or decreasing the volume of the sound...
, although Grand Concert Series (GCS) and classical models were also produced from the early 1970's onward. Dreadnought models DM-5 and DR-7 are the most common early Sigma guitars until the late '70s (D for dreadnought
Dreadnought (guitar type)
Dreadnought is a type of acoustic guitar body developed by guitar manufacturers C.F. Martin & Company. The Dreadnought style has since been copied by other guitar manufacturers and is now a common style of guitar body...
R for rosewood
Rosewood
Rosewood refers to any of a number of richly hued timbers, often brownish with darker veining, but found in many different hues. All rosewoods are strong and heavy, taking an excellent polish, being suitable for guitars, marimbas, turnery , handles, furniture, luxury flooring, etc.In general,...
, M for mahogany
Mahogany
The name mahogany is used when referring to numerous varieties of dark-colored hardwood. It is a native American word originally used for the wood of the species Swietenia mahagoni, known as West Indian or Cuban mahogany....
and the number denoting the grade, 7 being the top grade instrument). Construction moved from Japan (1970-83), to Korea (1984-93/94), and finally Taiwan (1993-2007).
In 1980, model lines were added to capitalize on Martin model numbers: the DM-18, DM-19, DR-28, DR-28H,
DR-35, DR-41, and DR-45. The DM-5 and DR-7, as well as other early models continued to be built during this time as well.
Sigma guitars made in Japan from 1970 through 1979 can be distinguished by a headstock
Headstock
Headstock or peghead is a part of guitar or similar stringed instrument. The main function of a headstock is holding the instrument's strings. Strings go from the bridge past the nut and are usually fixed on machine heads on headstock...
logo consisting of the single word SIGMA surmounted with the Σ symbol (the Greek letter sigma), in mother of pearl
Nacre
Nacre , also known as mother of pearl, is an organic-inorganic composite material produced by some mollusks as an inner shell layer; it is also what makes up pearls. It is very strong, resilient, and iridescent....
. The sigma symbol is often described as a "sideways M." Interestingly, while playing a Sigma guitar the "sideways M" becomes "right side up" suggesting "M" for Martin.
Sigma classical guitars do not have the headstock logo, and one must rely on the inner label for identification.
Made in Japan Sigma's (1970 through the late '70s) had an inner paper label giving model and serial numbers. "Sigma Serial Numbers do not provide an indicator of the year in which a particular model was built. However, most Sigma models were offered only for a limited number of years, so that most models' construction dates can be narrowed down to a reasonable range." For example, serial numbers on the earliest DR-7s start with 4 digit numbers on through 5 digit numbers. One Sigma DR-7 owner stated "I have an old Sigma DR-7 Guitar....s/n 6860. Bought it new in 1970." Further, DR-7s with a four digit ink stamped serial number and a zero fret strongly suggests a very early build date. Later, early 70's Sigma guitar serial numbers started with 7* suggesting the 197* build date. "Sigma Martin USA" guitars built in the early 80's had serial numbers 900,001 to 902,908. Serial numbers for Sigma guitars built in Korea and Taiwan are perhaps meaningless.
In 1980 the paper labels were discontinued and the back brace was stamped. With the move of production to Korea in 1984, paper labels (of a different design) were reinstated although some early 1984 models still retained the back brace stamp.
In 1979 Sigma identified their dreadnought and grand concert guitars as "Second Generation" and the headstock design changed to utilize a gold decal stating "Sigma Guitars" with "Est. 1970" underneath, in the familiar Martin headstock decal form. High end models such as the D-10 Anniversary model have the "Second Generation" logo in mother of pearl. Guitars made in Taiwan have a different headstock label: "Sigma Guitars" on top with a miniature version of the "C.F. Martin & Co." label underneath.
The issue of whether or not Sigma guitars are solid wood or laminate
Laminate
A laminate is a material that can be constructed by uniting two or more layers of material together. The process of creating a laminate is lamination, which in common parlance refers to the placing of something between layers of plastic and gluing them with heat and/or pressure, usually with an...
wood has been a source of controversy and confusion. This is understandable since the Martin customer service department now responds to individual inquiries stating "all" Sigma's had laminate back/sides with solid tops while Sigma catalogs from the early to late 70's list the back/side wood as solid.
To complicate matters further, in the mid-to-late 70's Sigma produced a line of guitars clearly identified by Martin, at that time, as having laminate backs and sides: model numbers starting with 52S, e.g., 52SDM-5, 52SDR-7 and 52SGCS-7. The answer to the question "Are Sigma guitars solid wood or laminate?" is best answered "That depends on the year and model." Later Sigma guitars, i.e., Second Generation, had laminate wood for the back and sides, with the exception of several models such as the D-10 Anniversary guitar.
Other Sigma instruments included mandolins, banjo
Banjo
In the 1830s Sweeney became the first white man to play the banjo on stage. His version of the instrument replaced the gourd with a drum-like sound box and included four full-length strings alongside a short fifth-string. There is no proof, however, that Sweeney invented either innovation. This new...
s, acoustic and electric bass
Bass guitar
The bass guitar is a stringed instrument played primarily with the fingers or thumb , or by using a pick....
es and solid body
Solid body
A solid-body instrument is a string instrument such as a guitar, bass or violin built without its normal sound box and relying on an electric pickup system to directly receive the vibrations of the strings....
and hollow body
Semi-acoustic guitar
A semi-acoustic guitar or hollow-body electric is a type of electric guitar with both a sound box and one or more electric pickups. This is not the same as an electric acoustic guitar, which is an acoustic guitar with the addition of pickups or other means of amplification, either added by the...
electric guitars. Some solid body electric guitar
Electric guitar
An electric guitar is a guitar that uses the principle of direct electromagnetic induction to convert vibrations of its metal strings into electric audio signals. The signal generated by an electric guitar is too weak to drive a loudspeaker, so it is amplified before sending it to a loudspeaker...
s were made by Tokai Guitars Company, LTD.
After Sigma musical instruments were built in Japan, Korea, and Taiwan, they were sent to Martin & Co. in Nazareth, Pennsylvania
Nazareth, Pennsylvania
Nazareth is a borough in Northampton County, Pennsylvania, in the United States. The population was 6,023 at the 2000 census.Nazareth is located seven miles northwest of Easton, four miles north of Bethlehem and twelve miles northeast of Allentown...
to be inspected and adjusted by Martin personnel before going to the authorized retail store for retail sale.
The DR-28 was manufactured in Japan, Korea and Taiwan while the SDR-28 appears to have been manufactured in Japan (SDR-28H, with the H signifying a herringbone inlay pattern) and Korea only, starting in early 1984. The DR-28 was of a solid Spruce top and laminated Rosewood sides and back while the SDR-28 was made with a solid Spruce top and solid Rosewood sides and back.
The DR-28 and SDR-28 are clones to the original Martin D-28 guitar and are high quality Sigma’s.
Basic Characteristics of Made in Japan Sigma Guitars
From 1970 to approximately 1975:- Adjustable bridgeBridge (instrument)A bridge is a device for supporting the strings on a stringed instrument and transmitting the vibration of those strings to some other structural component of the instrument in order to transfer the sound to the surrounding air.- Explanation :...
on all dreadnought (except DJ-7) and GCS models - Martin style peghead with adjustable truss bar through peghead from 1970 through 1979.
- PegheadHeadstockHeadstock or peghead is a part of guitar or similar stringed instrument. The main function of a headstock is holding the instrument's strings. Strings go from the bridge past the nut and are usually fixed on machine heads on headstock...
is a unique style that differs from the traditional Martin peghead design - Original peghead logo Sigma with Greek symbol Σ above
- The first year 1970 DR-7 has a zero fret
From approximately 1975 to 1984:
- Nonadjustable bridge
- Martin style peghead with adjustable truss bar through peghead from 1970 through 1979. Truss Bar adjustments were accessed through the sound hole from 1980 forward.
- From approximately 1980 through 1984, with few exceptions, back brace stamps were used instead of a paper label
- Original peghead logo Sigma with Greek symbol Σ above until 1979
- 1979 onward, logo stating "Sigma Guitars" with "Est. 1970" underneath
1970 to approximately 1975
- CS-6 Classical guitar. Mosaic marquetryMarquetryMarquetry is the art and craft of applying pieces of veneer to a structure to form decorative patterns, designs or pictures. The technique may be applied to case furniture or even seat furniture, to decorative small objects with smooth, veneerable surfaces or to freestanding pictorial panels...
around sound holeSound holeA sound hole is an opening in the upper sound board of a stringed musical instrument.The sound holes can have different shapes: round in flat-top guitars, F-holes in instruments from the violin or viol families and in arched-top guitars, rosettes in lutes. Bowed Lyras have D-holes and Mandolins may...
. Rosewood bridge. SpruceSpruceA spruce is a tree of the genus Picea , a genus of about 35 species of coniferous evergreen trees in the Family Pinaceae, found in the northern temperate and boreal regions of the earth. Spruces are large trees, from tall when mature, and can be distinguished by their whorled branches and conical...
top. Back and sides bubinga wood. MahoganyMahoganyThe name mahogany is used when referring to numerous varieties of dark-colored hardwood. It is a native American word originally used for the wood of the species Swietenia mahagoni, known as West Indian or Cuban mahogany....
neck. Rosewood fingerboardFingerboardThe fingerboard is a part of most stringed instruments. It is a thin, long strip of material, usually wood, that is laminated to the front of the neck of an instrument and above which the strings run...
. Pearl buttons on machine headMachine headA machine head is part of a string instrument ranging from guitars to double basses, a geared apparatus for applying tension and thereby tuning a string, usually located at the headstock. A headstock has several machine heads, one per string...
s.
- CR-7 Classical guitar. Mosaic marquetry around sound hole. Back and sides rosewood. Top made of finest close-grained spruce. Carved peghead. Neck mahogany. Flat-oval neck. Top and back binding black and white. Lacquer finish.
- DM-5 Dreadnought. Spruce top. Mahogany back and sides. Black and white binding. Natowood neck. Rosewood fingerboard. Nickel-silver fretFretA fret is a raised portion on the neck of a stringed instrument, that extends generally across the full width of the neck. On most modern western instruments, frets are metal strips inserted into the fingerboard...
s. Open in-line tuning machines. Adjustable rosewood bridge. Adjustable truss rod through peghead from 1970 through 1979. Unbound peghead.
- DR-7 Dreadnought. Spruce top. Matched rosewood back and sides. Back and sides have black and white binding. Rosewood overlay on peghead. Peghead bound in white. Adjustable truss rod through peghead from 1970 through 1979. Rosewood fingerboard. Adjustable rosewood bridge. Pearl inlay position markers on fingerboard. High gloss lacquer finish.
- DJ-7 Dreadnought. Spruce top. Brazilian jacarandaJacarandaJacaranda is a genus of 49 species of flowering plants in the family Bignoniaceae, native to tropical and subtropical regions of South America , Central America, Mexico, and the Caribbean. It is also found in Asia, especially in Nepal...
sides. 3 piece matched grain jacaranda back with marquetry. Peghead bound in white. EbonyEbonyEbony is a dense black wood, most commonly yielded by several species in the genus Diospyros, but ebony may also refer to other heavy, black woods from unrelated species. Ebony is dense enough to sink in water. Its fine texture, and very smooth finish when polished, make it valuable as an...
fingerboard. Mother of pearl inlays on fingerboard. Fixed ebony bridge. Natowood neck. Adjustable truss rod. Black and white binding. Satin lacquer finish.
- DM12-5 12 String Dreadnought. Spruce top. Mahogany back and sides. Black and white binding on back and sides. Rosewood fingerboard. Unbound peghead. Open inline tuning machines. Adjustable rosewood bridge. Adjustable truss rod.
- DM12-7 12 String Dreadnought. Spruce top. Rosewood back and sides. Black and white binding on back and sides. Rosewood fingerboard. Pearl position dotsFretA fret is a raised portion on the neck of a stringed instrument, that extends generally across the full width of the neck. On most modern western instruments, frets are metal strips inserted into the fingerboard...
. Adjustable rosewood bridge. High gloss lacquer finish. Peghead bound in white. Adjustable truss rod.
- GCS-6 Grand Concert. Spruce top. Mahogany wood back and sides. Mahogany neck. Adjustable rosewood bridge. Peghead bound in white. Rosewood fingerboard. Adjustable rosewood bridge. Adjustable truss rod.
- GCS-7 Grand Concert. Spruce top. Rosewood back and sides. Black and white binding. Rosewood fingerboard. Adjustable rosewood bridge. Gloss lacquer finish. White bound peghead. Adjustable truss rod.
Additional Models Approximately 1975 to 1978
These guitars still had the early peghead logo, instead of the "Second Generation Sigma" Martin style logo that started in 1979.- DT-22 Dreadnought. Spruce top. Tiger-striped mapleMapleAcer is a genus of trees or shrubs commonly known as maple.Maples are variously classified in a family of their own, the Aceraceae, or together with the Hippocastanaceae included in the family Sapindaceae. Modern classifications, including the Angiosperm Phylogeny Group system, favour inclusion in...
sides and back. Maple veneerWood veneerIn woodworking, veneer refers to thin slices of wood, usually thinner than 3 mm , that are typically glued onto core panels to produce flat panels such as doors, tops and panels for cabinets, parquet floors and parts of furniture. They are also used in marquetry...
on Martin style peghead. Tortoise shellTortoiseshell materialTortoiseshell or tortoise shell is a material produced mainly from the shell of the hawksbill turtle, an endangered species. It was widely used in the 1960s and 1970s in the manufacture of items such as combs, sunglasses, guitar picks and knitting needles...
binding around back and sides. Black pickguardPickguardA pickguard is a piece of plastic or other laminated material that is placed under the strings on the body of a guitar, mandolin or similar plucked string instrument...
. Fixed bridge has diamond shape inlays. Fingerboard has snowflake and diamond shape inlays. Pearl inlay between 19th and 20th fret (inscription not described in catalog).
- DR-7S Dreadnought sunburst. Martin style peghead bound in white. Spruce top. Rosewood back and sides. Rosewood fixed bridge. Adjustable truss rod.
- DM-5S Dreadnought sunburst. Unbound Martin style peghead. Spruce top. Mahogany back and sides. Rosewood fixed bridge. Adjustable truss rod.
- GCS-4 Grand Concert. Martin style peghead bound in white. Spruce top. Mahogany back and sides. Rosewood fixed bridge. Adjustable truss rod.
- CS-4 Classical Guitar. Spruce top. Mahogany back and sides. Mahogany neck. Rosewood fingerboard and bridge.
Sigma produced numerous "DR-*" models from the mid-70's on through 1984: DR-8; DR-9; DR-11; DR-14; DR-15; DR-28; SDR-28; DR-35; DR-41; and DR-45. During this period Sigma also produced a line of guitars with model numbers starting with 52S: 52SDM-5, 52SDR-7 and 52SGCS-7. 52S guitars had laminate backs and sides.
Special and Unusual Models
From 1980 through 1984, prior to construction being moved to Korea, Sigma produced several models that included electronic pickups: SE-18;SE-19; SE-28; SEMC-28 (with arched back); and SE-36. These models have saddles with each string individually compensated, yielding superb intonation. These models were produced in very limited quantities.In the early 80's Martin imported partially assembled Sigma guitars from Japan and the assembly was completed in Nazareth, Pennsylvania. There were two models, labeled "Sigma Martin USA DR-28N and DR-35N." A Martin factory sales brochure shows the DR-28N to retail at $600.00 and the DR- 35N to retail at $650.00 The DR-35N has laminate rosewood back and sides and a solid spruce top.The DR-28Nhad a two piece back and the DR-35Nhad a three piece back. The DR-35N had additional detail on the fretboard. The original factory brochure also states components were processed and finished on the same production line as regular Martins. The Head stock reads "Sigma Martin USA" and inside the sound box is " made in USA" with Martin address etc. Some consider the DR-35N to be a prototype of the inexpensive laminate Martin Shenandoah line of guitars. Since this model had serial numbers running from 900,001 to 902,908,. it appears that nearly 3000 Sigma Martin USA guitars were produced.
In 1980 Sigma produced 100 D-10 Anniversary guitars to commemorate 10 years of Sigma production in Japan. The D-10 has solid mahogany sides and back, solid select spruce top, rosewood fingerboard with diamond and square position markers, mother of pearl
Nacre
Nacre , also known as mother of pearl, is an organic-inorganic composite material produced by some mollusks as an inner shell layer; it is also what makes up pearls. It is very strong, resilient, and iridescent....
band stating "Anniversary" between the 19th and 20th fret, tortoiseshell type pickguard and binding, and close-ratio tuning machines. Regarding this guitar, Sigma enthusiast Sterling Webb stated "...equip one of these with a brass or ivory saddle, ebony bridge pins and medium strings and you can hunt down D-18s in the heaviest brush and stomp them to death...it's a very loud and impressive guitar!"