@tksteingraber Thanks for the thorough description of your listening impressions of the Linlai E-6SN7 tubes. Sounds like a good tube overall yet probably not one I want to add to my stable based on the weaknesses you noted.
The 1982 Melz 1578s have settled in very nicely as they accumulate more hours. I definitely place them in my top five. Still a touch forward in the upper mids but no longer objectionable. Their superb soundstage and bass continue to impress and, despite their reputation, one of the quietest tubes I own.
What’s up next for you? Perhaps a pair of Tungsol 6f8g round plates?