Gidday to anyone thats interested by the same facination with sigma guitars that i have been afflicted by since first strumming an old ex buskers DR28 for sale on behalf in a guitar shop many moons ago.
I have played gibsons,martins,takamine,larrivee and guild among others of similar stature but consider the tone produced by the japanese made guitar from this era as superior.
On close examination of the construction it appears to have laminate back and sides,solid,fine grained spruce top,20 fret neck,serial no.847721 made in japan stamped on the back brace(which would place the date of construction between 1979-1983)from 1984 on they were built in korea with different headstamp.
In my view,this guitar produces a loud full tone due to the quality of the spruce used for the top and attention to detail shown by the luthiers from japan who crafted the necks by hand and only used completely seasoned woods during construction,making a budget guitar from 50 year old components,i bet the folks at martin were impressed.
good on ya