Martin OM-18P Plectrum Guitar

Martin OM-18P Plectrum Guitar
Photos by William Ritter. Instrument courtesy of George Gruhn.
While the most commonly played and collected Martin guitars have a six-string neck, the company has also made a number of historically noteworthy four-strings.

Beginning in the 1920s and carrying into the ’60s, it produced several tenor guitars. In the ’30s, it offered plectrum guitars in an era when tenor banjos and guitars were far more popular. Tenor and plectrum guitars were primarily aimed at banjo players wanting to double on guitar. After the Dixieland music craze died in the late ’20s, musicians seeking to earn a living found far more opportunity by playing rhythm guitar than tenor or plectrum banjo, but many banjo players wanted to switch without learning to play a new instrument. Tenor and plectrum guitars appealed to them, as well as to banjo players seeking alternative sounds.

Tenor guitars were designed to be tuned the same as a tenor banjo – in fifths from low to high C, G, D, A – while plectrum guitars are tuned like a plectrum four-string banjo – C, G, B, D – same as a five-string minstrel banjo. Their four-string necks make tenor and plectrum guitars look very similar, but their scale lengths are notably different. At 27″, Martin plectrum guitars have the same scale as many Vega banjos. Tenor guitars typically had the short scale of a tenor banjo. Martin small-body (size 5) tenor guitars had a 221/2″ scale, whereas the company’s 0 size and larger tenors had a 23″ scale. In addition to making tenor guitars, Gibson made a small number of plectrum guitars with the same 261/4″ scale as a Gibson plectrum banjo.

Martin guitar necks had 12 frets clear of the body until 1930, when the company introduced the Orchestra Model (OM) with its new body shape and 14-fret neck. The OM-18P you see here is built to the same quality standards as the standard six-string OM-18. Typical of OM models, it has a 15″-wide body, Adirondack spruce top with scalloped bracing, and small, nitrocellulose tortoiseshell-grain pickguard. It has Grover banjo tuners of the style typically used on Martin OMs until 1931 (and on all pre-war tenor and plectrum guitars). Typical of a style 18 of this period, it has mahogany neck, back, and sides, ebony fingerboard and bridge, wood body binding, and Brazilian rosewood peghead veneer. Also typical of Martins made prior to late 1931, it has no decal on the front of the peghead, but has the C.F. Martin stamp on the back (standard on Martins until ’35). It’s also branded with the Martin logo on the interior vertical back stripe. The serial number and model number are stamped on the neck block. The company has stamped model designations on neck blocks since 1931.

Factory records indicate that 65 OM-18P guitars were made in 1931. When Martin first offered the model, it listed for $60, but the economy was being battered by the Depression, so, in ’32, the price was lowered to $50. In October of ’33, it settled at $55. Since all 65 examples were made in 1931 and Martin offered them through late ’33, it’s safe to assume it was not a hot seller. Martin commonly offered guitars as “new” even after they’d sat at the factory for several years. As long as it had not been previously sold, an instrument was considered new.

Though a significant number of tenor guitars and a limited number of plectrum guitars were sold, the instruments never replaced the standard six-string. Though both offer more sustain and a notably different sound compared to a tenor or plectrum banjo, they lack the bass response of a six-string. Orchestral rhythm jazz players of the big-band era, who worked without amplification, sought not only great volume and projection, but also wanted powerful bass response and thus, used heavy strings to achieve it. Many relied heavily on chord voicings utilizing the four wound strings more than the two unwound/treble strings, meaning they were effectively using the reverse of the sounds emphasized on a four-string tenor or plectrum guitar.

While not a great commercial success, plectrum guitars sound very good and are especially well-suited for Irish music tuned like a bouzouki or cittern. And this Martin is a fine example, with historical significance and collector’s appeal.


This article originally appeared in VG‘s April 2015 issue. All copyrights are by the author and Vintage Guitar magazine. Unauthorized replication or use is strictly prohibited.