Thompson OM-CA

A narrow-neck OM built with Cristobal granadillo.

August 14, 2025

Oregon’s Thompson Guitars has a knack for taking traditional flattop designs and making them their own. The current luthiers there continue to build on late founder Preston Thompson’s penchant for combining pre-war Martin specs with and sometimes surprising fresh features. I recently had a chance to check out a Thompson OM-CA that was a perfect example of that approach.

OM (Orchestra Models) are among my personal favorite guitars, and I’ve played many. The Thompson OM-CA is a stand-out example. This guitar — built on spec — features a gorgeous set of Cristobal granadillo for the back and sides. Cut in Costa Rica more than 75 years ago, the wood is lighter in color and different in density than the more common Mexican granadillo. The Adirondack spruce top has a sunburst finish. The OM style typically has a 1¾-inch nut and wide string-spacing at the saddle, but this guitar has a narrower neck with a 1¹¹/₁₆-inch nut and tight 2⅛-inch saddle spacing. The guitar has the long scale typical of OMs, but its overall feel is more like many 14-fret 000s with the same body size. You don’t need a spec sheet to realize that this guitar a one-off: While the sunburst finish wouldn’t be out of place on a vintage OM, the guitar’s “rope” purfling and rosette, walnut binding, and unusual walnut and mother-of-pearl fingerboard position markers give it a distinctive appearance. The guitar’s craftsmanship and fit and finish is superb.

With its narrow neck and string-spacing, the guitar was very well-suited for strumming and flatpicking, with the long scale providing a little extra string tension when compared with a similarly-spaced 14-fret 000. The Cristobal granadillo seemed to impart a tonal quality that leaned a bit more toward the brighter, sparklier character of a typical mahogany guitar, rather than the richness of a rosewood OM. The guitar has great sustain and a nice tonal balance, and while my relatively large hands found the neck and spacing a bit narrow for playing fingerstyle, many other players will find these dimensions quite comfortable.

The Thompson OM-CA confounds preconceptions, and it is remarkably inviting to play. At the time of our video shoot, the guitar wasn’t spoken for yet, so if this particular combination of specs and features tickles your fancy, give a holler to the fine folks in Sisters, Oregon.