This thread got me thinking about a pair of Viking RP61 tube preamps that was given to me from an estate some 20 years ago. Also included was a McIntosh MC240 amp and a MC20 preamp. I was given a nice Kennedy tool box with quality tools in it too so the fellow had good taste to say the least.
Anyway...the Viking`s were stuffed away until a couple years ago. I finally opened them up and ended up with a pair of Amperex Bugle Boys 12AU7 made in Holland with D7H printed on each of them.
I`m thinking I`ll bring them with me when I visit my daughter and son in law to try in their Rogue Sphinx II. Might be interesting to see what kind of change they make to the sound.