C.F. Martin 000-28K

Martin Koa image

Posted by Adam Perlmutter

The first time I saw Martin’s 000-28K Authentic 1921 was at the 2014 winter NAMM show in Anaheim, California, where this slender-waisted koa beauty stood out from the rosewood and mahogany dreadnoughts surrounding it. Lifting the guitar gently off its hanger, I was wowed by the lightness and the comfortable neck profile. But when I played it, I could scarcely hear a note, thanks to the collective sound of hundreds of electric guitarists nursing the minor pentatonic scale. It was important that I receive the 000-28K for a proper audition. Crucial, actually.

In Martin’s Authentic series, inaugurated in 2013, the company recreates prewar designs in exacting detail, using as many original materials and constructional methods as possible. The series includes a range of dreadnoughts from the early 1930s to the early ’40s, as well as a 1933 OM-18. 

While the original examples of most of those models are well-known to Martin aficionados, the same could not be said of the 1921 000-28K. Until now. That’s because the first 000-28K, which resides in Martin’s museum, was a one-off, not listed in the official production totals. It’s what makes this guitar such a special choice for reissue. 

The Design & Details

Unlike a modern flattop, which typically has a 14th-fret neck-to-body junction and a solid headstock, the 000-28K is a 12-fret model with a slotted headstock. This older design effectively reduces access to the upper register, but to many ears, it offers a superior sound. 

To recreate the 000-28K, Martin scanned it using CT technology (see Call the Doctor, page 62) to obtain a precise set of measurements. Like the original, the new Authentic model has a delicate build, with the woods used for the top, back, and sides fashioned much thinner than on a typical modern Martin. In keeping with tradition, there’s no truss rod in the reissue, and it also has period-correct scalloped X bracing, made from 1/4-inch strips of Adirondack spruce. All of the components are adhered together with hot-hide glue, a traditional material that is more difficult to work with than a modern adhesive, and is said to offer both structural and sonic benefits. 

The most conspicuous difference between the original and this Authentic model is the wood used for the top, back, and sides. The example in the Martin museum is made from plain koa, but in this replica, Martin uses beautifully figured Hawaiian koa that possess a striking holographic effect when viewed from different angles. Martin also swapped out Madagascar rosewood for Brazilian on the headplate. But the straight-grained mahogany on the neck and the inky black ebony of the fretboard and bridge are identical to those seen on the original. 

Martin’s 28-series guitars are characterized by their plainness and minimum of ornamentation. The koa on the 000-28K Authentic, though, lends some opulence to the platform. Attractive vintage-correct detailing includes a herringbone-top inlay, a zigzag back strip, delicate snowflake inlays on the fretboard, and engraved side-mounted tuners with ivoroid buttons. The guitar is outfitted with a pickguard (a rare feature on an early 1920s Martin), whose tortoise effect is echoed in dots on the endpins. Given the beauty of the koa, it’s too bad the pickguard wasn’t included in the case so the owner could decide whether or not to install it. 

The 000-28K boasts unimpeachable craftsmanship. The frets are perfectly seated and smoothly polished, without a hint of jaggedness at the edges. The nut and saddle are impeccably notched. Not even an occasional anomaly is found in the guitar’s thinly applied finish, rubbed to a sumptuous gloss. The internal fit and finish are similarly well executed—there’s no glue creeping out of the braces or kerfing, or any other unwanted artifacts from the building process.  

The Feel & Sound

The 000-28K is every bit as sweet as I remember it being at the NAMM show. It’s featherweight at 3.6 pounds. The neck, with its 1-7/8-inch nut broadening to 2-5/16 inches at the 12th fret, is on the wide side—in fact, it’s just a hair narrower than that on a classical guitar. Still, despite my preference for narrow nuts, it does not feel straining when I play the 000-28K’s neck, which is shaped by hand to a profile what Martin refers to as an Authentic 1921 Barrel & Heel, a gentle and shallow V shape, as opposed to the club-like shapes found on some older necks. 

Because there is no truss rod in the neck, Martin recommends using custom light steel strings (it ships with a set gauged 11–15–23–32–42–52) or silk-and-steel strings, with their lower tension. These strings, coupled with Martin’s factory setup, make the guitar play effortlessly, almost like an electric guitar, whether on barre chords or single notes, and even when string bending. Of course, to maintain this playability, the guitar will likely eventually need a neck reset.

Because of the lightness of its build, it takes little effort to extract the loveliest tone from the guitar—warm and resonant, well balanced between registers—even with light strings. The instrument has the bell-like overtones and lush sustain characteristic of the best flattops. There is, though, something just slightly subdued about the sound. This is likely because koa is known to take its time in opening up to its full sonic potential. That the guitar already sounds this good is an indication that it will sound phenomenal after that process happens. 

Since the 12-fret guitar is a favorite among fingerstylists, it’s only natural to subject the 000-28K to some fingerpicking. In standard tuning, it’s deeply satisfying to play a range of selections, from country-style blues to Scott Joplin rags. The guitar is highly responsive to picking nuances; the notes blossom and meld together nicely, and they dirty up just so when I really dig in. When in DADGAD tuning, bass notes retain their depth and presence, but fretted notes on the highest string experience a slight loss in headroom before distorting, an effect that can perhaps be worked around with a heavier string for the player who works exclusively in lowered tunings. 

While the 000-28K doesn’t have the volume of a dreadnought, it sounds quite good when strummed, with robust bass and a good separation between notes. It works just as well for basic open chords as it does altered seventh chords in closed positions. Flatpicked single-note lines also fare well, with ample presence and definition.

A Golden-Era Gem

With the 000-28K Authentic 1921, Martin has recreated a golden-era koa gem that few people knew existed. This finely crafted guitar boasts excellent playability and a lovely voice that will surely sound even better as the koa opens up.

At a Glance


• 000–12-fret body size.

• Solid highly figured Hawaiian koa top, back, and sides. 

• Polished gloss finish with aging toner.


• Genuine solid mahogany neck with no truss rod. 

• Ebony fretboard and bridge.

• 25.4-inch scale length.

• 1 7/8-inch nut width.

• 2 3/8-inch string spacing at saddle. 

• Stew-Mac Golden Age tuners with ivoroid knobs.


• Martin M535 Phosphor Bronze (Custom Light) strings.

• 535V Harptone hardshell case.


$7,499 list;
$5,899 street.
Made in the USA. martinguitar.com

The lack of a truss rod, to say nothing of the hefty price tag, will no doubt limit the audience for this instrument. Those with the means and little concern with adjustability, though, will be rewarded with an heirloom-quality Martin that is sure to be endlessly rewarding to play.

Contributing editor Adam Perlmutter transcribes, arranges, and engraves music for numerous publications.

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