A mono cartridge is by far the best way to experience mono records. Playing a mono record with a stereo cartridge will not achieve the same signal in both the left and right channels. It will not be “true mono”. Imperfections such as crosstalk, phase errors, and tracking errors will result in a degradation of sound quality. Using a mono cartridge eliminates these problems by only producing one signal that is then distributed to both speakers on your stereo system.
Full feature on why a mono cartridge is best:
https://www.yoursoundmatters.com/do-you-need-a-mono-cartridge-to-play-mono-records/
Full Ortofon 2M Mono Cartridge Review with audio samples:
https://www.yoursoundmatters.com/ortofon-2m-mono-review-does-a-mono-phono-cartridge-sound-better/
Amazon Affiliate Link (2M Mono): https://geni.us/2mmono