That loose like a fun project.

The Schiit Buffer looked like a single tube gain stage with a SS Buffer when I first looked at it. "Hybrid" in the description kind of gave it away. I do like that most of the gain can be cut with a flick of the switch.
If you look through that link I posted you will see the "Color Preamp" too.
Its meant really for a SS amp to add some tube flavor, but Stephie built one with a few tweeks thats interesting. I seem to remember a thread she started on it along with a YouTube video on her channel about her build.
I've thought about building the color preamp for my very minimumalist garage system consisting of a Crown power amp, soeamers and a bluetooth reciever. But I'll probably just buy the Schiit Buffer instead.