Gibson MB-3 Mastertone #645-1
Prewar Gibson literature promised that the mandolin-banjo combined "a certain portion of the mandolin sweetness with brilliancy, volume and tone quality of the banjo into one marvelous instrument." Gibson had heavily promoted mandolin orchestras in its earlier years, and with the increased popularity of banjo ensembles in the 1920s the mandolin-banjo was touted as providing an essential "sweet soprano voice in the banjo band."
This 1936 (see Gibson banjo serial numbers vs. factory order numbers) MB-3 features the same pot construction found on style 3 Mastertone tenor banjos of the period, with a one-piece flange and forty-hole raised-head tone ring. The mandolin neck has fifteen frets and is inlaid with the "diamonds and squares" pattern which had been standard on style 3 Mastertones of the 1920s. Most unusually for a mandolin-banjo, #645-1 has four strings rather than eight; it was shipped on April 24, 1936 as a "special" MB-3 to Gibson teacher-agent Dee Wells of Louisville, Kentucky. The instrument was returned to Gibson for an unspecified repair and sent back to Wells on May 25, 1936, this time listed as a "special four-string" instrument. The pearloid head guard is not listed in either ledger notation but is factory original equipment. #645-1 remains in its original #393 case by Geib and Schaefer. The tailpiece has been replaced.
Photos courtesy of an anonymous collector.