I bought a bunch at a rummage sale in the 90s, but I'm not parting with them!
6SN7GT VT231 TUBES
I love the old VT231 tubes!
The best sounding 6SN7GT ever...Sylvania, Raytheon, RCA, Ken Rad Etc. They may still be found, if you have $$$!! Where can I find true NOS VT231s? Any favorites that I missed?
(TS never made a VT231 - but their old black glass tubes with oval micas sound great!)