My system has been basically the same for more than 25 years except for the CD player. ARC pre, LS2B MKII + remote takes a 6DJ8 but has been on a diet of late 1960's to early 1970's 6922 Cca Siemens and Halske grey plate NOS for the last 20 years. Did a big shoot out 20 years ago and except for one stint with a Valvo pinched waist 6922 Cca from 1958 it's been all Siemens. The problem is 20 years ago they were plentiful as brand new never used @ $80 a tube and now they are $400 or more for a tube that still meets NOS readings. There are no new ones I can find so fortunately I will live with the three new ones I still have in stock before trying out some Russian Rockets from the 1970's that are new and were highly touted. AFAIC, the best are long gone.
How expensive are best NOS tubes ? And how difficult to find ?
Phono stages, preamps and power amps. Any non-Chinese adequate substitutes? I know that if you have Lamm, Vladimir has a few sets of Russian tubes in stock for each particular unit, and it is not really expensive to retube them. But if you have, say, VAC or CAT or Atma-Sphere and want best longest lasting and most reliable tubes, what then ? Don't ask me why not Chinese, I can't talk about it here except that I don't trust their quality control.