The Electro-Theremin is an electronic musical instrument developed by trombonist Paul Tanner and amateur inventor Bob Whitsell in the late 1950s to produce a sound to mimic that of the theremin.

[citation needed] Tanner played it for the 1958 LP record Music for Heavenly Bodies, the first full-length album featuring the instrument,[3] and played it subsequently on several television and movie soundtracks, including George Greeley's theme for the 1960s TV series My Favorite Martian and on an LP record titled Music from Outer Space.

[citation needed] Tanner played his Electro-Theremin on four songs by The Beach Boys: "I Just Wasn't Made for These Times", "Good Vibrations", "Wild Honey" and a studio outtake written by Dennis "Tune L", The instrument used in "Good Vibrations" was a Heathkit tube-type audio oscillator coupled to a mechanical action that allowed the player to mark notes along a ruler-type scale where notes could be located quickly and precisely.

In the late 1960s, Tanner donated or sold the instrument to a hospital to use for audiology work, because he believed that newer keyboard synthesizers made it obsolete.

[4] In 1999, Tom Polk built a replica of the original Electro-Theremin for Brian Wilson's solo tour of that year.