I need a tube buffer circuit using a 12au7

[Bigun]

For the record (and for Andrew), this topology is called Taylor/White (Or so I think: in case I am wrong, I'm sure plenty of kind members will rush in to correct me 😀)

The Taylor follower adds a transistor into the mix. It results in improved PSRR.

Taylor Source Follower

 

[kodabmx]

A 6N6P would work much better for your purposes and costs less.