Hollow State Design” is a unique new book that all about rediscovering the fun and magic of building electronic circuits with vacuum tubes—or “thermatrons,” as the author prefers to call them!

Recreating information once thought to be lost or spread over many obscure volumes, this excellent new book contains everything you could ever possibly need to know about the art and science of vacuum tube design and circuit construction.

There is nothing else in print today that compares with “Hollow State Design!”

It pulls together, in one easy-to-read book, thermatron types and their characteristics, thermatron homebrew techniques, and practical how-to design of audio and RF triode and pentode circuits.

The book is quality printed on 233 pages, standard 8.5” x 11" in size, and is packed with hundreds of photos, schematics, diagrams, plus charts and formulas that are essential when working with electron tube technology in the 21st Century.

The author, Grayson Evans (TA2ZGE/KJ7UM) has been licensed since 1962 and grew up on thermatrons. He spent 40 years in the professional electronics industry, and is now bored to death with solid-state projects!