Here is a new video presented by the San Francisco Audiophile Society in which David Berning gives an overview and history of OTL tube amplifiers, and of particular interest a thorough explanation of his own ZOTL circuit. Unfortunately the video is long, and it's not until about 30 minutes in that he gets into the ZOTL function and how he arrived at this solution that allows a tube amplifier to work without the typical wire-wound audio output transformers. Much of it is also quite technical (to me anyway), but I'm sure the many forum members here well-versed in electrical engineering will get a better understanding. If they have enough patience to get through it that is! But this does add to the forum's information database.
