as a whole and felt that it lacked authenticity, calling McCartney's contributions "[music] for the grannies to dig" and not "real songs", and describing the medley as "junk ... just bits of songs thrown together". Technical aspects Abbey Road was recorded on eight-track reel-to-reel tape machines rather than the four-track machines that were used for earlier Beatles albums such as Sgt Pepper, and was the first Beatles album not to be issued in mono. The album makes prominent use of guitar played through a Leslie speaker, and of the Moog synthesizer. The Moog is not merely used as a background effect but sometimes plays a central role, as in "Because", where it is used for the middle eight. It is also prominent on "Maxwell's Silver Hammer" and "Here Comes the Sun". The synthesizer was introduced to the band by Harrison, who acquired one in November 1968 and used it to create his album Electronic Sound. Starr made more prominent use of the tom-toms on Abbey Road, later saying the album was "tom-tom madness ... I went nuts on the toms." Abbey Road was also the first and only Beatles album to be entirely recorded through a solid-state transistor mixing desk, the TG12345 Mk I, as opposed to earlier thermionic electron vacuum valve-based REDD desks. The TG console also allowed better support for eight-track recording, facilitating the Beatles' considerable use of overdubbing. Emerick recalls that the TG desk used to record the album had individual limiters and compressors on each audio channel and noted that the overall sound was "softer" than the earlier valve desks. In his study of the role of the TG12345 in the Beatles' sound on Abbey Road, music historian Kenneth Womack observes that "the expansive sound palette and mixing capabilities of the TG12345 enabled George Martin and Geoff Emerick to imbue the Beatles' sound with greater definition and clarity. The warmth of solid-state recording also afforded their music with brighter tonalities and a deeper low end that distinguished Abbey Road from the rest of their corpus, providing listeners with an abiding sense that the Beatles' final long-player was markedly different." Alan Parsons worked as an assistant engineer on the album. He later went on to engineer Pink Floyd's landmark album The Dark Side of the Moon and produce many popular albums himself with the Alan Parsons Project. John Kurlander also assisted on many of the sessions, and