Hi @edgewear
Yoshihisa Mori was close friends with Kanemori Takai, and after Mori left Sony, he was involved in a variety of projects, one of which would have been the creation of a cartridge production line inside Final.
FWIW, Final was originally formed by two brothers with the family name of Kitamura; I was friends with them before Takai-san acquired the brand and merged it with his own Takai Laboratory.
Due to Mori-san's friendship with Takai-san, and his high-ranking position within the Sony corporate organization, I believe that Mori was able to obtain special dispensation for Takai-san to use the XL-88D design and suitable components from Sony's parts-bins.
Since Sony by that time was so heavily focused on digital (eventually Mori became the head of Sony's SACD division, and came to be called "Mr. SACD"), the cartridge IP was no longer of much value to Sony.
As you write, the body is that of an XL-44 (the XL-55 looks similar but has a different finger-lift design, among other detail differences). Small scratches reveal the underlying plastic to be of a different color than the metal-blue surface, therefore the color was painted onto the plastic rather than being molded into it (as would have been done for real bespoke production).
The coils appears to be of the coreless figure-8 type, which was the final coil design that Mori-san settled on for its MC designs.
I can't comment about the damper choice, as this is not visible from the photos. However, the damper-to-cantilever matching is one of the key aspects which can make or break a cartridge's sound, and given the size and production volume of Sony's cartridges division, they would have possessed a range of different rubber compounds and shapes. Therefore it wouldn't be a surprise if Takai-san chose a different set of dampers to the XL-88D, and if so, the sound wouldn't have been the same.
Again as you write, the joint-pipe is long and the one-piece stylus-and-cantilever diamond section short on this sample, showing that this used the standard XL-88D configuration rather than following the extreme and costly Custom.
Finally, since the body is of the integrated-shell variety, this cartridge must be used with a universal-type tonearm. The universal headshell connector, although widely adopted for its convenience, has a number of fundamental design flaws will most likely limit the performance level that can be extracted from this cartridge.
Still, this could have been a very interesting purchase. The screwed-on copper top was most likely added to make working on it easier than the molded-and-glued-shut Sony originals.
Too bad the auction seems to have ended (wonder what it ultimately sold for).
kind regards, jonathan
Amazing! I've seen this cartridge before several times, but the full story is awesome. Thanks Jonathan.