If your mono cartridge has four pins, it's technically a dual-mono cartridge. Just connect it as you would any stereo cartridge. A true mono cartridge (one channel only) will have two pins, and will require a little more work to mount on a standard (4-wire) tonearm rig.
Mounting a Mono cartridge
How do you mount a mono cartridge ? Do you simply connect the 4 cart pins to the corresponding wires on the tonearm as in a stereo cart or is there more to it ? This is in the context of a Ortofon 309D with a Miyajima BE mono cart. Would appreciate any help and advise
Cheers
Cheers