The Beatles • The original UK LPs

From Wikipedia:

In their native United Kingdom during 1962–1970, the Beatles released 12 studio albums, 13 EPs, and 22 singles. However, the band’s international discography is complicated, due to different versions of their albums sometimes being released in other countries, particularly during their early years on Capitol Records in the United States. The Beatles’ discography was originally released on the vinyl format, with full-length long plays (LPs), shorter EPs, and singles. Over the years, the collection has also been released on cassette, 8-track, compact disc (CD), and on a USB flash drive in MP3 and 24-bit FLAC format. Although their output has come to include vault items and remixed mash-ups, the core Beatles discography recorded during the 1960s is 217 songs (including 4 songs in two different versions and 2 songs in German) and approximately ten hours of music.

Most of the Beatles’ albums were released in both mono and stereo. Since mono record players were the most common at the time, the Beatles and their regular producer George Martin gave more time and attention to preparing mono mixes of their recordings. The Beatles had involved themselves in creating only the mono mixes for the first four albums; the stereo mixes were prepared without their supervision. However, because by the late 1960s stereo record players became more common, their final two albums—Abbey Road and Let It Be—were mixed and released in stereo only.

From 1968, in both the UK and the US, starting with the single “Hey Jude” and the album The Beatles (better known as the “White Album”), new releases appeared on the Apple label. Parlophone and Capitol catalogue numbers continued to be used for contractual reasons.

The Beatles’ UK discography was released on CD in the late 1980s. According to the official editions of the first four albums, they were released in mono. The remaining albums were then issued in stereo only. However, the sound of the digital transfers of the discs, produced by George Martin in 1987 and 1988 using the best equipment available during the early days of the format, no longer met the standards achievable of 21st century techniques. From 2005, over a four-year period, the original recordings were remastered using the latest technology. Apple and EMI released this version of the Beatles’ catalogue on CD on 9 September 2009 (i.e., 09-09-09, as in, “number nine, number nine, number nine”) in mono and stereo.