Yes, have tried some of the Foton 6N8S, it's been a while but I remember they were solid performers, a little more emphasis in the upper bass/low mids but otherwise natural/neutral across the FR with good top and bottom extension and control. Purchased the '58 first, then '59, then one of the early '60s. Good quality also, not many noisy or microphonic tubes in any batch, maybe 10%, or less. Did prefer some of the better American counterparts from the same time period (GTBs), but some others that I shared these with preferred the Fotons. Agree, good value, I recall $6, in batches of 4 or 8. Never saw or heard the early '50s, however, so your '53s with ribbed plates may be better than the late '50s, which I think have smooth plates.
