During the 1990's Norman Koren designed a power amplifier using 6550 tubes and toroidal transformers. After correspondence with Menno van der Veen I have all of the information about the toroidal transformer that is used in Norman's Amplifier. Menno is the designer of this transformer and also has written a book that explains the theory about his transformers. The original PAT 4006 CFB transformer was special designed for Norman but for production Menno renamed the transformer to PAT 2100 CFB/H which is available at Plitron as well as Menno's book Modern High-end Valve Amplifiers based on toroidal output transformers.
I now have all of the parts on hand and work on the amplifier has begun. I am planning to modify the power supply slightly to include additional filtering and have wound a custom transformer. Toroid Corporation of Maryland has a transformer kit with the primary pre-wound and directions and charts to determine how to wind the secondary voltages. Kit number 402.070 supplies up to 700VA which will be more than enough power. This will allow me to supply all voltages from one transformer. I hope to have a prototype done soon which I can test with before I build the final amp. I am planning on building single driver horn speaker cabinets using Fostex FE206E speakers. I will be using the FE208ESigma cabinet designs.

This project has sat idle for over five years and has been little more than a "someday/maybe" project. My curiosity has grown probably larger than the amplifier can ever fulfill but before the year in over I should have a completed amplifier; it might surpass all expectations or it might be parts for the next amplifier. Please send my any technical thoughts.