Sigma SDJM-18 Slope-Shoulder Dreadnought (2011) – Adirondack / Solid Mahogany – Mint w/ ABS Case. Hard-to-find 2011 Sigma Guitars SDJM-18, a slope-shoulder dreadnought inspired by classic round-shoulder designs like the Gibson J‑45.
This model was designed by Sigma/AMI Germany and built with all-solid tonewoods, including a solid Adirondack spruce top and solid mahogany back and sides, giving it a powerful, vintage-style dreadnought voice with strong headroom and warm bass. These guitars appear regularly in European shops (especially Switzerland) with retail pricing around $1,290, making them a strong value for an Adirondack-topped, all-solid instrument.
See last photos on how it compares to the Gibson J-45 Studio.
Demo: https://www.youtube.com/watch?v=xGdjbvs216k
Mint condition. Only very light surface scratches from normal handling. No dings, cracks, repairs, or structural issues.
Includes an excellent Road Runner ABS molded jumbo acoustic guitar case (approx. $160 retail).
Specs
Model: SDJM-18
Body Style: Slope-Shoulder Dreadnought (Round Shoulder)
Top: Solid Adirondack Spruce (AA Grade)
Back & Sides: Solid Mahogany
Bracing: X-Bracing
Neck: Mahogany, Low Profile
Fingerboard: Ebony
Bridge: Ebony
Nut & Saddle: Bone
Construction: Dovetail Neck Joint
Scale Length: 25.4" (645 mm)
Nut Width: 1-3/4" (44.5 mm)
Frets: 20
Tuners: Grover Nickel with Butterbean Knobs
Truss Rod: Two-Way Adjustable
Finish: Polished High Gloss with Aging Toner
Included
Road Runner ABS Molded Jumbo Acoustic Case ($160 value)
A Bit of History
Slope-shoulder dreadnoughts trace their roots back to early large-body guitars built by C.F. Martin & Company for the Oliver Ditson Company in the early 1900s.
The large “Extra Large” Ditson guitars of 1916 eventually evolved into the modern dreadnought body shape we know today.