I've discovered that the Fosgate phono preamp is OK - happy day.
I've also given the Adcom some more listening time, and it sounds somewhat better. I don't know if it was:
1. Running music through the amp a couple of days improved the sound it produces, and/or
2. Running music through the amp a couple of days got me accustomed to the sound it produces, and/or
3. My mood improved, and/or
4. A cable change on the SACD player (from Kimber Hero to AQ King Cobra).
My initial listening was done with the SACD player, since I thought the Fosgate was dead, and the Adcom sounded terrible really, veiled and harsh at the same time, with a disjointed soundstage. Replacing the cable back to my standard King Cobra the next day, and/or all of the above, cured almost all of that. It still sounds a little hashy on busy percussion, with bongos and hand-claps kinda taking over on some songs on O'Samba, for instance. But it sounds much more civilized and coherent than at first listen. Not up to any of the Lux's, or the Hafler for that matter, from memory. But OK. Mine is unrestored, YMMV.
Really looking forward to the PrimaLuna!