Zero Time is the debut album by British-American electronic music duo Tonto's Expanding Head Band, released on 15 June 1971 by Embryo Records.

The album is a showcase for TONTO (The Original New Timbral Orchestra), a multitimbral, polyphonic synthesiser built by the two members of the band, Malcolm Cecil and Robert Margouleff, as a developed version of the Moog III synth in 1969.

Recording their compositions in New York, they approached TONTO with no pre-conceived notions and intended to make music intrinsic to the synthesiser.

In 1971, they set out to create music displaying the synth's versatility, with no intention of gaining financially from the material but instead to simply curate inimitable soundscapes.

"[7]In their book Analog Days, Trevor Pinch and Frank Trocco said the sounds Cecil and Margouleff produced were "neither kitschy, funny, nor imitative," and instead pushed the machine to its limits.

Cecil reflected that, instead of approaching TONTO with pre-conceived notions, they attempted to make music "intrinsic to the instrument," with the synth dictating how the duo progressed.

[10] The synth waves on the album are pristine and crisp, curating a "new sound that feels digital" according to Jim Brenholts of AllMusic.

[8] The cover features a painting by Carol Hertzer entitled Apollo on Mars,[8] which depicts a psychedelic montage showing stars, planets and swirling nebulae.

[17] Timothy Crouse of Rolling Stone was very favourable, despite finding the possibilities in using a Moog exciting and somewhat unsettling: "After all, a Moog theoretically can produce any sound, and produce it instantly, so that a clarinet might scale three mellow ascending notes and then on the fourth note play the sound of the sea giving up her dead.

"[23] Cecil and Margouleff only became aware of the album's acclaim when, in their words, "somebody brings us [the latest issue of] Rolling Stone and, lo and behold, there's a full-page article on how wonderful we are.

"[7] In their review, Billboard wrote that the duo "effectively travel to the outer limits of the Moog, including a 'vocal' by the machine," and concluded that the album would appeal to "the progressive undergrounders.

"[24] In Britain, Dick Meadows of Sounds felt that upon first sight, Zero Time would "put fear into the hearts of stronger men than me.

It is a classic with no real peers, but it will appeal to fans of Mother Mallard's Portable Masterpiece Company, Jean Michel Jarre, Tangerine Dream, Wendy Carlos, and Fripp & Eno in terms of its uniqueness and legacy.

"[11] Musician Julian Cope, also a musicologist,[26] wrote that Zero Time possessed some of the "warmest and most sweetly soothing sounds to arise from American synthesizer operators in the early months of the seventies."

He felt that the album utilised elements of the sounds that defined Paul Beaver's Moog experiments, and those on the soundtracks for The Trip (1967) and Performance (1970), while being lighter and more "stratospheric."

Although Zero Time quickly faded into obscurity, it was embraced by audiophiles upon release due to the pristine sound highlighting the strength of their speaker systems.

[7][28] Steven McDonald of AllMusic called the album "a revolutionary piece of work that set out to explore the capabilities of the synthesizer with no regard for conceptions of pop success," and wrote that it is "still considered to be a turning point in the use of synthesisers in modern music.

[5] Zero Time is also counted among the "classic Moog psychedelic records from the period" in the book Moments of Valuation: Exploring Sites of Dissonance,[10] while writer James McCarraher described it as a "synthesiser masterpiece.

"[23] Cope wrote that despite being less strident than purely electronic krautrock, some of the passages on Zero Time anticipated the "quieter paces" on side two of Kraftwerk's Autobahn (1974).

[13] Stevie Wonder had a chance encounter with Zero Time and became a big fan of the album, steering him in a new direction as he began using synthesisers in his music.

[29] He was so impressed with Zero Time that, taking a copy of the album with him, he met with Tonto's Expanding Head Band and said "I don't believe this was all done on one instrument.

[33] The album also influenced Devo, and Mark Mothersbaugh of the band said that, in the "cultural wasteland of the Midwest," the 1975 re-release of Zero Time was "an inspirational indicator for starving Spudboys who had grown tired of the soup de jour.

[4] The influence of Zero Time was the subject of an essay by Richie Unterberger included in the liner notes of the album's 2013 Real Gone Music reissue.