I'm new to the game and have been watching Skunkie's YouTube video's from about the start. I've made a little Elekit tube preamp and I'd like to get deeper into the hobby. I've read The TAB Guide to Vacuum Tube Audio by Jerry Whitaker.

I, however, would like to get a couple more books to read. What are some recommendations for a semi-technical guy.

Thank you in advance for any help.