After listening to 6n8s tube made in 1978 for several hours, I am back to Kenrad vt 231.
KR also has nice bass with sweet and refined atmostphere.
Definitely KR vt231 is at least half notch or even one notch above 6n8s .
Now I have 16 different variants of 6sn7 tubess.
After changing tube, sound also change as if new pre is being used.
It is like tasting various wines or coffees.
But if you do lot of tube rolling, be sure to use socket saver.