Can’t buy output tubes anywhere except from manufacturers at high prices.

There are plenty available on Ali Express.The prices have gone a bit silly but it is good to see that Chinese manufacturers have stepped in to the hole left in supply and production by the sanctions on Russia.

it seem the supply more little so the chinese company take oportunity

I have bought probably 40 sets of output tubes, rolling on multiple amps in the past 2 years.  Very few were chinese new production.  No, they aren't as cheap as they used to be.  But they are available from tube sellers, message boards, ebay, etc.  And sometimes the input/driver are harder to find in top quality, probably the toughest one is NOS 6SN7s.  Oh yeah, some rectifiers are not easy to find in top quality...but they are available.

300B you have to look around, but you can find them.  Or pay top dollar for Westinghouse.

Sounds like a monster opportunity for the new Western Electric factory. Hope they can step up and put U.S.A. tubes back on the map.

Note to self:

Don't buy tube amps, someone else will enjoy more.