How are you playing your precious MONO Vinyl?

If you look at graphs of the various curves generated by the different algorithms, they are not terribly different from one another, because after all the goal was essentially the same.  So I might be happily listening to some of my 50s mono LPs where the pre-emphasis was other than RIAA via the RIAA de-emphasis curve built into all my phono stages; I just don't hear a problem, except maybe with those Louis and Ella recordings on EMI, which date from 55 or earlier.

Here’s a question. Suppose you have a mono cartridge but don’t know whether it’s a true mono or a bridged stereo type. How would you tell the difference?

I asked essentially this same question a few years ago to the experts at Ortofon and the answer is there is no difference electrically and, therefore, no difference sonically.

The difference between what we are calling a true mono cartridge and a stereo cartridge that has been bridged to produce a mono signal in both channels is presumably that the true mono cartridge has had one of the pair of coils that serve each channel (assuming a MC design) either re-oriented so it does not pick up vertical movement of the cantilever, or there is no coil for that function. So my question really in disguise is what electrical measurement would tell you that? It is interesting that Ortofon responded to your question in the way you describe, because it was my experience a few years ago when I was investigating which cartridges are true mono, and which are not that Ortofon is very vague in describing how they derive their mono cartridges. As I recall, the description of the Quintet mono cartridge in particular was so ambiguous that one could not tell whether it was a true mono or a bridged stereotype. And I think that was deliberate. Surely the engineers at Ortofon do know the different ways to build a mono cartridge and the structural differences that result. Ortofon is not the only cartridge maker that leaves the question open or ambiguous.

@billstevenson If what Ortofon told you is true, then all of us who can hear a difference between a true mono cartridge and the mono button must be mistaken, which seems unlikely.

I spent a long time examining the description they give of the Cadenza Mono (which used the same wording at that time as for stereo Cadenza cartridges, and added the term "dual coil mono") and ended up buying one. It doesn't get used—I'll happily sell it—as it doesn't sound anything like as nice as the Ruby 3 I had converted to mono (coil assembly rotated 45° and the laterally sensitive coil connected to both sets of pins).