Sigma Guitars

Sigma Guitars is a musical-instrument brand established by C.F. Martin & Company in 1970 as an answer to the growing availability of lower-priced guitars imported from Japan and other Asian manufacturing centers. Rather than positioning the line as a wholly separate design tradition, Martin used Sigma to offer instruments that drew on familiar American acoustic-guitar formats at prices below its primary Martin range. The early assortment concentrated on dreadnought acoustics, while grand-concert, classical and other models were also introduced. Manufacturing was international from the beginning. Sigma instruments were initially produced in Japan by several factories between 1970 and 1983. Production then moved to South Korea from 1984 through 1994, with Taiwan also involved during the 1994 transition period, and later to Indonesia before the Martin-era line ended in 2007. Instruments were imported to the United States and inspected or adjusted by Martin personnel before being supplied through authorized dealers. This arrangement gave the brand a relationship with Martin quality-control practices while allowing production costs to remain lower than for Martin-built instruments. The early range included laminate-bodied dreadnoughts such as the DM-5 and DR-7, with the letters generally indicating dreadnought, mahogany or rosewood construction and the number indicating a model grade or specification level. In 1978, Martin expanded the model nomenclature with instruments such as the DM-18, DM-19, DR-28, DR-28H, DR-35, DR-41 and DR-45. These later models, commonly described by collectors as second-generation Sigmas, generally featured solid-wood tops and specifications more closely associated with Martin-style instruments. Models including the DR-28, SDR-28 and SDR-28H became particularly noted for their rosewood construction, spruce tops and, in the SDR versions, scalloped bracing and herringbone-style appointments. Sigma also extended beyond standard acoustic guitars. Across its history the brand was associated with classical guitars, acoustic basses, electric and acoustic-electric instruments, mandolins, banjos and ukuleles. Some solid-body electric models were produced by Tokai, while other instruments came from different Asian factories. The changing factories, headstock designs, labels, logos and serial-number conventions have made dating and authentication a specialist activity for owners and collectors. Serial numbers can provide clues but are not consistently reliable because several factories used overlapping or poorly documented systems. Martin discontinued Sigma in 2007. AMI Musical Instruments GmbH acquired rights to the name in 2011 and relaunched the line with instruments manufactured in China. The modern international range includes acoustic and classical guitars, acoustic basses and ukuleles, and continues to emphasize recognizable, traditional guitar formats at comparatively accessible prices. A separate trademark complication affects the United States: Martin's U.S. rights to the Sigma name had lapsed before the transfer, and St. Louis Music subsequently obtained those rights. AMI therefore markets its corresponding instruments in the United States under the Kindred Guitars name, while continuing to use Sigma in other markets.

C.F. Martin & Company introduced Sigma Guitars in 1970 during a period when imported Asian guitars were becoming increasingly competitive in the United States. The line allowed Martin to participate in the value-oriented segment while retaining control over the brand concept, specifications and inspection process. Early Sigma guitars were made in Japan by multiple factories. The most common early instruments included dreadnought models such as the DM-5 and DR-7, alongside grand-concert and classical designs. The first-generation instruments commonly used laminate construction, although the range varied considerably by model and factory. Sigma's visual identity evolved during the Japanese period. Early instruments often had a squared or spatula-like headstock and a logo visually related to Martin's typography. Later examples acquired a more tapered headstock and a gold script decal identifying Sigma Guitars, sometimes accompanied by an “Est. 1970” marking. Labels inside the instruments also changed over time, moving through black-and-white, gold and purple designs before some late-1970s models used a branded center back brace instead of a conventional paper label. These details, along with tuners, bridge construction, finish and trim, are now used by collectors to estimate production dates. In 1978 Martin introduced a group of higher-specification model designations modeled on its own numbering conventions. The DM-18, DM-19, DR-28, DR-28H, DR-35, DR-41 and DR-45 formed an important part of this second-generation identity. Many featured solid spruce tops and more elaborate appointments than the earliest Sigma models. The DR-28 and related rosewood dreadnoughts became prominent examples of the brand's effort to provide Martin-like tonal and visual characteristics at a lower price. The SDR-28 and SDR-28H, associated with later Korean and Taiwanese production, added features such as scalloped bracing and herringbone-style binding. A small group of Sigma-Martin instruments was partly assembled at Martin's Nazareth, Pennsylvania facility in 1981 and 1982. The DR-28N and DR-35N used specially assigned serial-number ranges and were completed sufficiently in the United States to carry a Made in U.S.A. designation under the rules applicable at the time. These instruments are distinct from the larger body of Sigma guitars that were manufactured overseas and then inspected or adjusted by Martin personnel. Manufacturing moved from Japan to South Korea in 1984. Taiwan became involved during the 1994 model year, and later production moved to Indonesia. The line also included classical guitars, acoustic basses, electric and acoustic-electric instruments, mandolins and banjos. Some electric models were made by Tokai. The broad manufacturing network meant that serial-number systems were inconsistent, and serial numbers alone generally cannot establish an exact production year. Certain 1981–1982 U.S.-finished instruments are an exception because their serial ranges were documented by Martin. Martin ended the Sigma line in 2007. In 2011 AMI Musical Instruments GmbH acquired rights associated with the name and relaunched Sigma internationally, with current instruments produced in China. The modern catalog includes acoustic and classical guitars, acoustic basses and ukuleles. The relaunch also exposed a territorial trademark problem: Martin's U.S. rights had lapsed before the transfer and were later secured by St. Louis Music. AMI consequently uses the Kindred Guitars name for its corresponding U.S. offerings, while maintaining Sigma branding in markets where it can legally do so.

• 2011

  AMI relaunches the brand

  [1]Sigma Guitarsen.wikipedia.org

  AMI Musical Instruments GmbH acquires rights connected with Sigma and revives the brand internationally with Chinese production.

• 2007

  Martin-era Sigma production ends

  [1]Sigma Guitarsen.wikipedia.org

  C.F. Martin & Company discontinues the Sigma line after production in Japan, South Korea, Taiwan and Indonesia.

• 1994

  Taiwan enters the production history

  [1]Sigma Guitarsen.wikipedia.org

  The 1994 model year includes instruments made in both South Korea and Taiwan as manufacturing changes continue.

• 1984

  Production shifts to South Korea

  [1]Sigma Guitarsen.wikipedia.org

  After the Japanese manufacturing period, Sigma production moves primarily to South Korean factories.

• 1981

  Sigma-Martin instruments are completed in Nazareth

  [1]Sigma Guitarsen.wikipedia.org

  The DR-28N and DR-35N are partly assembled and finished at Martin's Pennsylvania facility.

• 1978

  Second-generation model designations appear

  [1]Sigma Guitarsen.wikipedia.org

  Martin adds models such as the DM-18, DR-28 and DR-45, with many featuring solid tops and more Martin-like specifications.

• 1970

  Sigma Guitars is introduced

  [1]Sigma Guitarsen.wikipedia.org

  C.F. Martin & Company launches Sigma as a value-oriented guitar line designed to compete with imported Asian instruments.

Accessible, Martin-influenced guitars and related string instruments manufactured through international production partnerships. The brand appeals to players seeking traditional dreadnought and classical designs, familiar specifications and strong value without the price level of premium American-made instruments.

• Steel-string dreadnought acoustic guitar

  DM-5

  The DM-5 was one of the most common early Sigma dreadnoughts. Its designation is associated with a mahogany-oriented construction and an entry-level specification within the early range. Japanese examples are generally regarded as first-generation instruments and commonly used laminate construction. The model represents Sigma's original purpose: providing a recognizable, traditional acoustic-guitar format at a price below Martin's principal American-made catalog.

• Steel-string dreadnought acoustic guitar

  DR-7

  The DR-7 was a widely produced early rosewood-oriented dreadnought. It appeared in the Japanese period and is frequently encountered in vintage Sigma collections. Construction and appointments changed over its production life, so individual examples need to be assessed through labels, headstock details, serial-number format and hardware rather than by model name alone.

• Steel-string dreadnought acoustic guitar · 1978

  DR-28

  The DR-28 is a Martin-influenced rosewood dreadnought associated with Sigma's later, higher-specification model family. It generally combines a solid spruce top with laminate rosewood back and sides, although specifications depend on production period and country. The model was made in Japan, South Korea and Taiwan and became one of the best-known Sigma instruments.

• Steel-string dreadnought acoustic guitars

  SDR-28 and SDR-28H

  The SDR-28 and SDR-28H are enhanced rosewood dreadnoughts associated mainly with Korean and Taiwanese production from the mid-1980s onward. Compared with standard DR models, the SDR instruments are noted for solid spruce tops, scalloped top bracing and herringbone-style decoration. They were designed to deliver a more elaborate, Martin-inspired specification while remaining part of Sigma's accessible imported range.

• Classical guitars

  Classical guitars

  Sigma's classical range formed a parallel part of the catalog from the early years onward. Classical instruments typically used distinct headstock and labeling conventions, and many did not carry the external headstock logo found on steel-string models. Identification therefore often depends on the internal label, construction details and model information.

• Acoustic and classical guitars · 2011

  Modern Sigma acoustic and classical range

  Following AMI's relaunch, Sigma's international catalog returned to acoustic and classical guitars modeled around traditional forms. The current brand family also includes acoustic basses and ukuleles. In the United States, the corresponding AMI instruments are marketed under the Kindred Guitars name because of separate trademark ownership.

• 2011

  Transfer and international relaunch of the brandM&A

  Background

  AMI Musical Instruments sought to revive a recognized Martin-associated value brand after Martin's discontinuation.

  Action taken

  AMI acquired rights associated with Sigma and relaunched a broad range of instruments manufactured in China.

  Aftermath

  AMI continued using Sigma internationally but adopted the Kindred Guitars name for the affected United States market.

  Source

• 2007

  Discontinue the Sigma lineStrategy

  Background

  After decades of overseas production and multiple manufacturing transitions, Martin ended the original Sigma program.

  Action taken

  C.F. Martin & Company stopped producing Sigma-branded instruments.

  Aftermath

  The brand remained dormant until rights connected with the name were acquired by AMI Musical Instruments.

  Source

• 1970

  Create a value-oriented sister lineStrategy

  Background

  Imported guitars from Japan and elsewhere were increasing competitive pressure on established American manufacturers.

  Action taken

  C.F. Martin & Company introduced Sigma as an internationally manufactured line using Martin-related design cues and distribution oversight.

  Aftermath

  The brand developed into a large family of acoustic, classical and other string instruments sold through the Martin dealer network.

  Source

• Use Kindred Guitars in the United StatesOther

  Background

  Martin's United States trademark rights to Sigma had lapsed before the transfer, and St. Louis Music subsequently obtained those rights.

  Action taken

  AMI marketed its corresponding U.S. instruments as Kindred Guitars rather than Sigma.

  Aftermath

  The Sigma name remains associated with AMI's international offerings, while U.S. branding is territorially distinct.

  Source

1. 1Sigma Guitarsen.wikipedia.org
2. 2Sigma Guitars official websitesigma-guitars.com