In 1936, Gibson introduced the "Advance Jumbo" (AJ) acoustic guitar. With it's one-inch wider 16" lower bout, rounded or sloped shoulder dreadnought shape and a 25.5" scale length, the AJ was a powerful flat-top referred to in later Gibson literature as an "acoustic cannon." Today, this legendary design is carried over with Epiphone new AJ-220S acoustic guitar.
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