The Guitorgan started out in life as a Univox "Effie", a Gibson ES-335 copy. They were bought in quantity by Musiconics International out of Waco, Texas in 1969 and outfitted with organ parts. Each fret has six segments and when the string makes contact with the fret, the corresponding note sounds. It can be played as guitar, organ or both. It is believed that only about 3000 guitorgans were made. Bob Murrell is credited with its invention and Musiconics International (MCI) of Waco, Texas claims to have introduced the world to the Guitorgan.

The organ notes are typically keyed with switches on or under the frets. The guitar remains playable but organ notes can be played instead of or in addition to guitar chord. Murrell worked on converting existing products from the late 1960s. In 1968, he had a significant run of instruments based on semi-hollow body designs. The B300 and B340 are among the most common examples from this run. He continued to produce upgrades that included analog synthesizer interfaces and even midi in the mid 1980s.