Book Review: The State of Hollow State Audio in the Second Decade of the 21st Century
The things likely to strike any reader or potential buyer of this book are (1) the extremely long title and (2) the term ‘Hollow State’. Fortunately, the book cover helps to identify the subject at a glance by showing four large vacuum tubes (Br.E. ‘valves’), one of which is in brilliant focus to reveal its shiny glass envelope, internal structure and, importantly, the glowing filaments. The warm glow is also seen in the tubes that are out of focus.