A buddy of mine swore by these things when he got them. I brought up some NOS and premium current manufactured ones to compare. The 6sn7’s were beaten handily by in all cases by the Dawning series Shuguang, the Elite series Linlai, and Sylvania and RCA NOS. The Rays just sound very lean with weak bass and a bit harsh on the upper end. He also had a 12au / 12ax combination in an amp and they were destroyed by Telefunken and Siemens NOS. These are just re-branded standard issue tubes. The rest is just hype. If you listen to all the YouTube reviews the script is practically the same for all the reviewers.
