I’m coming to think that, playing "mono a mono" can be very good, but equally important is the stylus profile and general design of the cartridge - irrespective of whether it’s a mono or stereo design.
I think we have two things at play with mono cartridges. The obvious one being that it’s a true mono design (including rejection of vertical motion). The second factor that gets overlooked is that the stylus profile is more suited to the groove profile cut by a mono cutting head.
Taken another way, if "limited" to two varieties of cartridge (i.e. a dual tonearm rig), I’m more inclined to run a vintage stereo cartridge (i.e. Ortofon SPU) in the second position over a mono cartridge. I think this ultimately provides the flexibility to play more of your record collection.Â
This isn't to dismiss mono by any means ... just a slightly modified approach, and of course, if that second arm has a removable headshell, then one is free to collect a stable of easily swappable cartridges.
Cheers,
Thom @ Galibier Design