I have replaced all of the ECC82/12AU7 in my system with 6N8S (6H8C)/6SN7 inc. 2 x Chinese military metal base 6N8P T class they are stunning made ages before the Shuguang factory burnt down. I have replaced ECC83/12AX7 with 6N9P/6SL7. in the phono stage 2 x 6N2P EB OS now unobtainable. I x 6N1P cathode follower.
I have used a Ukrainian valve dealer for years, now I can't contact him we became almost pen/PC pals I pray he is OK! he sourced the 1958 Foton 6N8S & 1961 Reflector 6n9s same internal construction as the highly regarded Melz valves at considerably less cost.
I also kept all of the original valves for my Troughline stereo + a few extra EM84 magic eyes. also 4 x Baldwin(RCA) ECC82, , 4 RCA 6CG7 clear tops, 4 x 5814A, 2 x Mullard VC4004, 8 x Chinese military 1980's Bejing CV4004 (UK nuclear plant spares) 4 x 5751 8 x 5755 there are 10-20 others that I can't remember, oh nearly forgot 4 x new matched KT 120 power amp spares & 2 x 1957 Svetlana 5C3C,s (5U4G) winged C rectifiers.
I have 2 x spare 6N2P EB OS, liked by Bigman80, I introduced a friend in the trade to the OS he uses them in his expensive pre-amp & phono stage. as upgrades 20 x 6N2P all Voskhod 1960's - 1970's gold coils & pins triple mica. 12 x 6N6P Foton including very rare ones like below as Lampizator wrote
"It is a genuine Soviet design, unlike most of their tubes which they copied from the West all the time. The closest equivalent is the Ecc182, E182CC although the pinout is different, .
We do not want to use the impulse variant 6N6P-i later named 6N30P. We want the good old 6N6P only"
Lampizator's take on the 6N**P family
http://www.lampizator.eu/UPGRADE/upgrade noval tubes to 6H6P.html