No apologies necessary. Important info for tube buying.
What I discovered yesterday was that switching power cords went a long way towards eliminating the deleterious effects I had attributed to the EL51s. I’ve been using a full loom of PS Audio AC-12’s for a few years, but recently picked three used WyWires Palladians to check out, which I’d been told would maintain the modest warmth of the AC-12 while adding greater clarity (they do, both). In playing around with different locations for the WyWires, it wasn’t until they went onto the Oppo, TRP and Supratek preamp yesterday that I hit the jackpot — a smooth, relaxed, balanced sound and more consistently present midrange (e.g., female singers), without the shoutiness or seeming effects of the Tesla’s greater power. It’s a good reminder that the best solution to SQ problems introduced in changing tubes may lie in adjustments elsewhere (synergy).
Follow up: The above was written using a 596 in the TRP and a now burned in Brimar 5RGY in the Chardonnay preamp. I've since received a 1948 Philco 5U4G, which I found (inexpensively) after Dr. Steve Williams, who has his own system thread on these forums (Doctor's Orders-Part Two...), touted the benefits of a 1946 version in his excellent set up. He indicated that it is on warm side, which mine modestly is, as well as having an appealing touch of sweetness. It's now burning (or re-burning) in and has a lot to say for itself, although how smooth is to be seen. Philco tubes were made by Sylvania after the early 1930's, and sometimes had the latter's codes on them, starting around 1950 it seems. However, probably his and mine have the two character Philco code still used in the 1940's, e.g., S8 for some quarter of 1948.