Some information on cartridges and styli
On a mono record the groove moves only side to side. Therefore the stylus in a mono cartridge only has to have sideways movement. For stereo the groove also move vertically so the stylus has to move from side to side and up and down.
The terms for these movements are horizontal compliance for mono and vertical compliance for stereo If we were to play stereo record using a mono cartridge there would be no up and down movement and therefore the stylus would carve its way through the vinyl and eventually cause irreversible damage.
At Dansette when we are replacing the cartridge we always fit wherever possible a new stereo cartridge. This covers all eventualities. Original cartridges are in very short supply.
There is a trade off though as the stereo cartridge does not give as much output as the mono variety, most noticeable in a single valve amplifier So you may not rattle the windows at the 60s rave but at least your records will survive longer.
Should you prefer mono then we can always fit this as an alternative. As a rough guide, records were being made in stereo from probably the mid 1960s or mid Beatles era.