<P> Vinyl's lower surface noise level than shellac was not forgotten, nor was its durability . In the late 1930s, radio commercials and pre-recorded radio programs being sent to disc jockeys started being pressed in vinyl, so they would not break in the mail . In the mid-1940s, special DJ copies of records started being made of vinyl also, for the same reason . These were all 78 rpm . During and after World War II, when shellac supplies were extremely limited, some 78 rpm records were pressed in vinyl instead of shellac, particularly the six - minute 12 - inch (30 cm) 78 rpm records produced by V - Disc for distribution to United States troops in World War II . In the 1940s, radio transcriptions, which were usually on 16 - inch records, but sometimes 12 - inch, were always made of vinyl, but cut at ​ 33 ⁄ rpm . Shorter transcriptions were often cut at 78 rpm . </P> <P> Beginning in 1939, Dr. Peter Goldmark and his staff at Columbia Records and at CBS Laboratories undertook efforts to address problems of recording and playing back narrow grooves and developing an inexpensive, reliable consumer playback system . It took about eight years of study, except when it was suspended because of World War II . Finally, the 12 - inch (30 cm) Long Play (LP) ​ 33 ⁄ rpm microgroove record album was introduced by the Columbia Record Company at a New York press conference on June 18, 1948 . At the same time, Columbia introduced a vinyl 7 - inch ​ 33 ⁄ rpm microgroove single, calling it ZLP, but it was short - lived and is very rare today, because RCA Victor introduced a 45 rpm single a few months later, which became the standard . </P> <P> Unwilling to accept and license Columbia's system, in February 1949, RCA Victor released the first 45 rpm single, 7 inches in diameter with a large center hole . The 45 rpm player included a changing mechanism that allowed multiple disks to be stacked, much as a conventional changer handled 78s . The short playing time of a single 45 rpm side meant that long works, such as symphonies, had to be released on multiple 45s instead of a single LP, but RCA claimed that the new high - speed changer rendered side breaks so brief as to be inaudible or inconsequential . Early 45 rpm records were made from either vinyl or polystyrene . They had a playing time of eight minutes . </P> <P> Another size and format was that of radio transcription discs beginning in the 1940s . These records were usually vinyl, 33 rpm, and 16 inches in diameter . No home record player could accommodate such large records, and they were used mainly by radio stations . They were on average 15 minutes per side and contained several songs or radio program material . These records became less common in the United States when tape recorders began being used for radio transcriptions around 1949 . In the UK, analog discs continued to be the preferred medium for the licence of BBC transcriptions to overseas broadcasters until the use of CDs became a practical alternative . </P>

When did the first 45 record come out