In fact, looking over the whole thread I’m not sure who I recalled suggesting that mono records played with a stereo pickup will be too noisy.That was probably me, but I need to clarify that I was only referring to vintage 1950s-’60s mono LPs, not modern reissues. I have several from both categories. I have several modern mono reissues--the 2014 Beatles EMI/Parlophone reissues, the Capitol Beach Boys reissues including Pet Sounds and Smile, Acoustic Sounds Nat King Cole reissue, etc. All are really quiet, even when played by a stereo cartridge.
OTOH, I have many original 1950s-60s mono LPs rescued from bargain bins for 50-99 cents, that are totally noisy with all 3 of my stereo carts and totally quiet with my one mono cart.