Dennis, my impression of the NOS Tung-Sols and Sylvania VT-231s mirrors yours in my Blue Circle BC21. Early this past spring when I was buying up tubes on Audiogon, I managed to snag three NOS US Navy Ken-Rad VT-231s dated January and February 1945. I've enjoyed the Sylvanias so much that I stopped rolling the tubes in my BC21, but I've always wanted the qualities you describe in the Ken-Rads. The Ken-Rads will be going in my Blue Circle right now, I'll report back in a few days.
Black glass KenRad 6SN7s take the cake
I've been experimenting with 6SN7s in my VAC 70/70:
ElectroHarmonix: good tube! and great for the price. Much better than I though it'd be, but ultimately sounded too edgy and sterile. Good control throughout, and good detail.
Sylvania VT231: twinkly and brilliant; great detail, tight bass, but much less fatiguing than the ElectroHarmonix; nice and smooth, but still lacking in the mids for me.
TungSol black glass, round getter: better than the Sylvania, in that it was a bigger sound. Lost the twinkly and brilliant quality. Good detail. Good overall, balanced tube. Nothing outstanding I thought, relative to the other tubes I tried.
KenRad, tall, black glass: THESE KICK!! very lush, deep, BIG BIG sound; the absolute best midrange; detail was good, and surprisingly, this tube is NOT DARK. very smooth, and less reserved sounding than the other tubes. Let's it loose... and that's the one drawback; the bass isn't as tight the TungSol or the Sylvania, but it didn't annoy me. What I gained from this tube far outweighed this drawback.
...that's just what I thought of these tubes in MY system. Who knows if these qualities translate to other pieces.
ElectroHarmonix: good tube! and great for the price. Much better than I though it'd be, but ultimately sounded too edgy and sterile. Good control throughout, and good detail.
Sylvania VT231: twinkly and brilliant; great detail, tight bass, but much less fatiguing than the ElectroHarmonix; nice and smooth, but still lacking in the mids for me.
TungSol black glass, round getter: better than the Sylvania, in that it was a bigger sound. Lost the twinkly and brilliant quality. Good detail. Good overall, balanced tube. Nothing outstanding I thought, relative to the other tubes I tried.
KenRad, tall, black glass: THESE KICK!! very lush, deep, BIG BIG sound; the absolute best midrange; detail was good, and surprisingly, this tube is NOT DARK. very smooth, and less reserved sounding than the other tubes. Let's it loose... and that's the one drawback; the bass isn't as tight the TungSol or the Sylvania, but it didn't annoy me. What I gained from this tube far outweighed this drawback.
...that's just what I thought of these tubes in MY system. Who knows if these qualities translate to other pieces.