יש ברשת המון מאמרים בנושא.. לדוגמא זה:
https://www.yoursoundmatters.com/do-you-need-a-mono-cartridge-to-play-mono-records/
Why Bother with a Mono Cartridge then?
A mono cartridge is by far the best way to experience mono records. You could take the easy option and use a mono switch, but this will not fix the errors caused by a stereo cartridge never quite producing the same signal in both channels. In other words, 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. The signal in both your left and right speakers will be identical.
Using a mono cartridge can also reduce the response to dust and dirt substantially as any vertical element will not be reproduced. Often, the final result is a much cleaner reproduction of a mono record. Again, a mono switch cannot remove this noise—once the vertical element is tracked, it’s tracked, and this signal now has to be processed by the system whether you mono the signal retrospectively or not.
If ever there was a solid case as to why the signal source is more important than the signal
output, this is it!
A Note on Stylus Size
Depending on when your mono records were cut, the bottom groove radius may vary. For example, older microgroove records from around 1950 could approach 15µm or larger. For optimum performance, I have read sources that indicate these records should be played using a spherical 25µm (1 mil) stylus to avoid the risk of a stylus “bottoming out” inside the groove and causing poor fidelity.
Depending on who you ask, you’ll get a different answer as to when the bottom groove radius of mono pressings reduced. In truth, the groove size can vary quite dramatically. As a general rule, mono LPs mastered before 1970 were likely intended for playback using a 1mil stylus. After this point, they are probably cut with a modern 0.7mil in mind. That being said, other sources appear to suggest that the radius of mono record grooves decreased over time, firstly down to around 8µm in the mid-50s, followed by 4µm as we approached the dominance of stereo. A modern 18µm (0.7mil) stylus is perfectly safe for playing back records of both specs.
In an ideal world, listeners would own both the wider and slimmer variety to account for different microgroove specs. However, if finances prohibit this, go for a modern 17-18µm (0.6 – 0.7mil) option.
. 
