In The Groove - Mono
June 18th 1948, The Columbia Record Company announced their new consumer playback system. Whilst the 12” vinyl 33 ⅓ RPM had been used since the thirties for use on radio, it was the microgroove that improved audio quality and quantity.
The Mono microgroove records needed a 1mm conical shaped stylus for playback. Later Stereo records were cut with a .7mm V shape that needed a corresponding stylus to enjoy them. Once you upgraded your cartridge, not only could you enjoy music in all its wonderful lefty & rightyness, you would still be able to play your old mono albums in all their centrally placed audio. Try playing a stereo record with a mono stylus though and the effect is similar to a glacier cutting through a narrow valley. Most UK mono cutting lathes were gone by the end of the sixties and anyone using a modern 1.mm modern stylus on records cut after 1968 should be very wary. If in doubt, consult your dealer.
Some records like this one were sometimes mixed in mono for use by radio. Singles would be sent to DJ's that had a stereo version on one side and mono on the flip.
Paul McCartney ~ Ram (mono reissue)
The original pressing was a very limited one that was intended just for radio and it contains some different mixes (albeit quite subtle ones), for this reason it became very collectable and naturally, very expensive! Modern mono reissues like this are cut with the stereo type groove but both channels have exactly the same information.