What kind of magnetic cartridge?

[jr_tech]

If I remember correctly, stereo records became mainstream in 1958.

“1958: Shure introduces the M3D stereo Dynetic Cartridge. It is the world's first moving magnet stereo cartridge and features stereo channel separation at 1,000 Hz of 20 dB or better.”

from: https://service.shure.com/s/article/...language=en_US

jr