Valve circuits are crude and simple, but it's very old obsolete technology and you struggle even buying decent valves these days, and there's very little choice.I've never done anything with tubes. They seem kind of daunting to me.
As far as I was aware, the Russian valves have always been poor quality, both for their sound and their reliability, and the Chinese valves have been even worse.Actually...there are a few Russian valve manufacturers and they (russians) still have huge stock piles of superb sounding specimens and very cheap to purchase too...
That blew my mind when I was first starting out in radio at the age of 12 or 13.One device whose operation is not understandable using conventional current flow
Mazda were good as well, we used to fit large numbers of valves, including a few industrial ones - we ran a couple of valve based cable systems, and those used industrial valves.Telefunken, RCA, and I believe Mullard back in the day (1960s) made the very best valves.