SimpleBass is an Italian custom bass workshop based in Invorio, in the province of Novara, founded by luthier and bassist Roberto Musso. The project grew out of Musso's two decades playing a fretless Jazz Bass and his desire to build an instrument that retained the slim neck and passive electronics of that template while extending the fingerboard and refining the body shape. Each instrument is built to order, with a name and serial number, from a rotating selection of tonewoods including mahogany, curled and spalted maple, swamp ash, African ebony, ebony Macassar, zebrawood, wengé, American cherry, European spruce, alder, and blue poplar.

The lineup centers on a small number of handcrafted models. The e4 is a 4-string fretless with an extended fingerboard, single-coil Alnico pickup, and roughly 33.46-inch scale. The Fusion II is an active electric bass offered in 4, 5, and 6-string fretted or fretless configurations, designed around lightweight ergonomics. The EX is a single-cut active model in similar string and fret configurations, and the Aix is a hollow-body bass pairing a magnetic pickup and piezo bridge through an active two-band preamp. The workshop also builds an electric upright that uses a real double bass bridge with a floating ebony fingerboard, and, under the Chromatone Guitars name, a line of solid-body electric guitars with a 25-inch scale and 20-inch fingerboard radius.

SimpleBass is closely associated with Italian bassist Gianni Gadau, who has played and demonstrated the Fusion model in clinics and online videos, and the brand circulates largely through European bass communities and word of mouth rather than mass distribution.

SimpleBass has 4 products cataloged on Equipboard, including Electric Basses, Upright Basses, and Fretless Basses. Their gear is featured by 1 artist, with the strongest followings in Rock and Jazz. Notable users include Ares Tavolazzi.