The RCA 12AU7 clear tops are readily available from numerous sources. The Sylvania, as plentiful as Sovteks five years ago, are nearly vanished, the demand is so high. The source I have used has only a few left, and, heartless as it may seem, I have a friend (Susan above) that I am holding my tongue for.
I have one spare pair. Both Rt008 and I are looking for a tube that will prove to be a close second. He still likes the Chinese tubes that came with the Jolida. I wonder if I can find mine?