What I find interesting is that the tracking force for the D72 - D74 styli is 1 - 1 1/4 grams. Which makes sense, since they were for P-mount carts. But the paperwork that came with the D75S lists tracking force as 3/4 - 1 1/2 grams - as for the standard mount cart in the box.
Strangely enough, I’ve also seen other Stanton literature, including this brochure
http://www.vinylengine.com/library/stanton/p-mount-series.shtml and another more complete cartridge catalogue that I got from somewhere, specifying the D73S and D74S (or the cartridges they were fitted to) as having either 0.75 – 1.25g tracking force, or 0.75 – 1.5g! So I don’t know if they changed the styli, or were just inconsistent in their literature (other examples tend to support the latter:thumbsdn

!
When did Stanton move to Florida?
I’m not sure exactly when Stanton moved to Florida, but suspect it was either 90’s or early-2000’s.
Were the hi-fi 680 carts replaced by the 681 versions (excluding the disco 680EL and 680HP versions) at some point? If so, maybe the unmarked cart in this set is actually a nice 681 variant (it's black), and not the 680EE-S cart. Any thoughts?
The ‘1’, as used in the 681, 881 and 981 variants of the 680, 880 and 980 series, just indicated that the particular cartridge had been individually measured and ‘calibrated’ to meet a strict frequency response standard. Someone mentioned a 581 as well, but I don’t know anything about it.
They were sold alongside the other models - for instance the 880S and 881S were both sold alongside each other at various times, as were the 980 and 981 series. There doesn’t appear to have been a calibrated version of the 600 series.
So most of the 680 series cartridges are 680's, apart from a few 681’s, which include the 681SE and 681A (both Disco versions with higher tracking forces, designed for ruggedness), 681EE, 681EE-S, 681-S, 681EEE and 681EEE-S. There were also MkII and III versions of some of these.
So for example, an 880S was exactly the same as the 881S, but the 881S was measured and guaranteed to meet certain standards, while the 880S wasn't. In fact, Stanton say in several brochures, that the performance was effectively the same between the '0' and '1' versions.
Of course, the calibrated models cost more due to the extra work involved in testing them individually. That was probably why they sometimes sold them alongside each other - not everyone wanted to pay extra for a bit of paper, but professionals who wanted consistent sound probably were happy to, and could probably justify the cost. Some audiophiles may also have wanted the snob value - you can just imagine, "Oh - you've only got the 680EE - I've got the 681EE!"
If so, maybe the unmarked cart in this set is actually a nice 681 variant (it's black), and not the 680EE-S cart. Any thoughts? I also have a VERY similar (also black) cart that came with a EEE-II-S stylus. The model number on the cart simply says 681. To complicate things even more, I have (what looks like) an older black 680EE/S cart that came with a stylus that simply says D680 S. It sounds fine, but the D75S sounds much nicer.
They did make a few differently coloured variants over the years, but I dodn't know what the colours depicted. They also made a lot of 680's, as it dates back to the late-60's. They kept improving it too - at one stage, the 680EE/681EE was the top model, until the 681EEE made an appearance in the (I think) early-70's.
In my listening tests (I did a few more), the D75S sounds better than my D73S. It also sounds better than my D74S stylus - although, in fairness, my D74S has a lot of hours on it, and the D75S is NOS. I tested all the styli on the same 681EEE cart.
I really wish I had saved that styli chart I saw a while back that listed the frequency response of the D75S. Proof would help a lot. I remember it going up to 30K Hz, and making a mental note that i wanted to track one down. Now that I finally have one, I'm sure happy I got it - it just sounds perfect.
There are plenty of Stanton (and Pickering) brochures, many in English, some in German, at Michael Otto’s archive here
http://new-hifi-classic.de/Gallery_MO/index.php . I had a look through, but couldn’t see the D75S anywhere, so it certainly sounds like it was a special.
I suppose there must be some difference between the D73S, D74S and D75S. The chart you posted above does show that the D74S is specified as being slightly better than the D73S, so maybe the D75S is better again - that would account for it sounding better.