I remember only one company that made a tube based HT preamp/processor. I can't remember the exact model and google doesn't show any results, but I'm pretty sure it was made by Audio Design Associates (ADA). I remember seeing pictures of it in magazine ads as well as website. This was in the early 2000's (probably around 2001-2005). I don't remember anyone actually having it and I have no idea if they sold any at all. The product picture showed about 5-6 tubes lit up inside, probably 12ax7 tubes for audio stage.
Coincidentally, ADA was probably the earliest implementation of Trinnov room correction system. They don't exist anymore, lol.
Coincidentally, ADA was probably the earliest implementation of Trinnov room correction system. They don't exist anymore, lol.