Sigma Guitars - Basic Characteristics of Made in Japan Sigma Guitars

Basic Characteristics of Made in Japan Sigma Guitars

From 1970 to approximately 1975:

Adjustable bridge on all dreadnought (except DJ-7) and GCS (Grand Concert Series) models, but this too is an inconsistency as not all had the adjustable bridge.

Peghead is a unique shape that differs from the traditional Martin peghead design in that it is more square than tapered, as the later 2nd Gen models were.

Original peghead logo Sigma with Greek symbol Σ above

Adjustable truss rod through peghead.

The first year 1970 DR-7 has a zero fret as well as some of the 12-strings did to approximately 1973 or 1975 (DM12-5.)

From approximately 1976 to 1983:

Nonadjustable bridge, often showing a pair of pearloid screw covers.

Martin style peghead (tapered)

"Martin style" decal peghead logo stating "Sigma Guitars" in script with "Est. 1970" underneath in a smaller block font.

In the early 1980s, some special instruments, such as the D-10 Anniversary, and DR-28H models, have an inset pearl/pearloid logo. The "Est. 1970" is underlined in these cases.

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, or "brands" were used instead of a paper label.

Tuning Machines

There were only a few types of tuning machines used during these years. All were basic and inexpensive. There are three different shapes of the buttons on these tuners. Oval in the early models, a more square shape ala' Schaller in style in the middle years, and a keystone shape on later versions.

The lesser 6-string models, such as the DM Mahogany series, had open-backed, 3-on-a-plate non-adjustable "economy" tuners in the earliest years. Later ones, were individual machines, but looked exactly the same from the front.

The 12-string models had open-back "6-on-a-plate" (non-adjustable/economy) tuners.

More upscale models, such as the DR Rosewood series, had the same tuners only with chromed cover over them. These were all non-adjustable and held in place by two opposing screws (corner to corner) on the back of the headstock and are still available today.

Early Rosewood series model 12-string guitars (pre-1975) had non-adjustable covered "6-on-a-plate" ala' Kluson style tuners. Later versions (approximately 1976 onward) were individual, non-adjustable, as on the 6-stringed models (14:1 ratio.)

Most 6-string "upscale" models from 1981-1983 instruments had adjustable sealed tuners, but the 12-string models continued with the covered (non-adjustable) "economy" tuners (14:1 ratio.) Others continued on using the cheaper tuners.

The earliest sealed tuners, maybe as early as 1972, had a 6-sided cast body and no brand name (11:1 ratio,) while there were others later on that more resembled Schaller (stop screw to the inside) or Grover tuners (stop screw below but without the familiar crescent knob.) Few of these sealed tuners were branded at all, while others in later years show "Sigma" stamped on their backs.