@barnettk- btw: The reason I like to suggest that particular 6922 variant comparison; the things/aspects/sense of realism, that the author listens to and for, precisely mirror my own. By the time I heard about that one year (1975) run of the Russian Grail, the prices were nuts. As happy as I've been, with my sets of the early Sixties, grey shield, Siemens CCa and E188CC, gold pins: I've no regrets. Glad I bought them all, way back when the prices weren't as salty (25+ years) Here's a good treatise, on why the CCa designated tubes are as good as they are:
https://www.tubemuseum.org/ProductDetails.asp?ProductCode=SH%2DCCA%2D1963 Keep in mind, as you read that; it's all about QUIET, in a phono stage.