12-inch 45 rpm records were introduced in the 1970s.
what year were 12-inch 45 rpm records introduced?
1970s
the 7-inch 45 rpm record was released 31 march 1949 by rca victor as a smaller, more durable and higher-fidelity replacement for the 78 rpm shellac discs. the first 45 rpm records were monaural, with recordings on both sides of the disc. as stereo recordings became popular in the 1960s, almost all 45 rpm records were produced in stereo by the early 1970s. columbia records, which had released the  rpm 12-inch vinyl lp in june 1948, also released  rpm 7-inch vinyl singles in march 1949, but they were soon eclipsed by the rca victor 45. the first regular production 45 rpm record pressed was "peewee the piccolo" rca victor 47-0146 pressed 7 december 1948 at the sherman avenue plant in indianapolis, r.o. price, plant manager.
single (music)
in the spring of 1946, "rca victor" replaced "victor" on labels for shellac 78 rpm singles. in 1949, rca victor introduced the 7-inch 45 rpm micro-grooved vinylite record, marketed simply as a "45". the new format, which had been under development for several years, was rca victor's belatedly unveiled alternative to the 12-inch and 10-inch 33⅓ rpm microgroove vinyl "lp" (long play) discs introduced by arch-rival columbia records in the early summer of 1948. in heavy promotion, rca sold compact, inexpensive add-on and stand-alone units that played the 45 rpm format exclusively. at first, rca victor's 45s were issued on colored vinyl according to the musical genre: contemporary pop music on black vinyl (47-xxxx series), prestigious broadway musicals and operettas on "midnight blue" vinyl (52-xxxx series), classical music on red vinyl (49-xxxx series), country and polka on green (48-xxxx series), children's fare on yellow (also in the 47-xxxx series), rhythm and blues on orange or cerise (50-xxxx series), and international on light blue (51-xxxx series). this array of colors complicated the production process and the practice was soon discontinued, all records became black. yellow and red held on until about 1952. the first 45 rpm record manufactured was "peewee the piccolo" rca victor 47-0147 pressed december 7, 1948 at the sherman avenue plant indianapolis, r.o. price, plant manager. the use of vinyl, which was much more expensive than the gritty shellac compound normally used for 78s, was actually cheaper because of the smaller diameter and greatly reduced bulk of the new records, which required very little raw material. the smaller, lightweight discs were also more economical to store and ship.
rca records