This is an interesting speaker. I saw one once but had no idea what it was at the time or how much it might be worth. Wish I had bought it but oh well live and learn. There isn't alot of information available. Below are pictures articles and snippets I've found of the Catenoid.
The Audio League Report Vol.1 No.10 November 1955.
Tube of the Month: The 211 (revisited) - Hi! The 211 / VT4C was already covered extensively in the Tube of the Month of July last year. Judging by the clicks that post received and still receives...
12 hours ago