After reading about Mordy's experience with his FIVRE-Ferrari heptodes, I came across some FIVRE-Ferrari 6AT6/EBC90 triodes, and thought, why not?
These look different than any other EBC90 or EBC91 I have seen, so perhaps they will sound different? Like a Ferrari? lol Interestingly, on the inside of the box, the name "Dr Hans Borklin......Munchen.... -8 Sep 1958" is stamped in black ink. (Munchen = Munich, it seems....) I have Googled this gentlemen, but no results.... This suggests these were likely manufactured in the mid-1950s.
And then, since MIKELAP has been very impressed with his Japanese-made Hit-Ray, I thought it might be interesting to try some Japanese triodes. Found some Japanese-made 6AV6/EBC91 sourced by Multivox for use in their synthesizers in the 1970s. Again, these look entirely different than any other triode I have ever seen, so again, perhaps these will sound different?
And finally, a pair of Tung-Sol 6DT6 arrived:
GE 6HZ6 update. These tubes have about 12 hours on them, and I think I like them better than the Sylvanias. They have more bass presence than the Sylvanias and the midrange and treble remind me of the 8425. But again, these are very superficial first impressions, only ten minutes or so, of casual listening......