Russian Tube Preamp, No Return, Here I go again

Why do you wish for 12AU, T, or X7s?

They are popular, simple, the goof ball valves are NEVER a good choice for a build, just a cheap way. 50 cent valves in surplus Russia.. LOL

I know exactly why they used them.. They can!!

They are not the only ones to use TV tubes to build stuff.. 6NS7 very popular NOW, sure wasn't 25 years ago..
WHY, surplus and cost.. they use to be dirt cheap, surplus.. Carys favorite valve..

Regards

Order one from China next time, just to mix it up a little.

Reasonable gamble for a relatively low price. Only advice I have is I would not hook directly into your main system right away. If you have some spar components that you don't care about then feed into them first and see how it goes.

High Gm tubes like 5687 and 6922 types are “goofball”?

Uh, for the money, It looks well worth the gamble. Nice find.