I had one of the Head SUTs that I inherited a while back, but didn't know anything about it, or it's apparent respect from those who did! Sold it on quite quickly for a fair price as I never used it, or intended to, but discovered later how rare and respected it actually was. Sigh!
Why don't you contact Ear Yoshino directly, who should be able to provide you with some history and spec details? (Tim de Paravicini still responds to enquiries).
Technics SL1000R, DynavectorXV1t, Garrard 401, Jelco SA750LB, Decca Reference, ATVM750SH, AT33Mono, Hana Umami Red, Reimyo CDP777, EarYoshino 912, Ear Yoshino 509s, JBLK2 SL5800s, ART Dram interconnects / speaker cables.