[jrblasde]

Fantastic report, Mr. Fixr! I had never read about AC/DC sets originally running at a higher price than AC-only models, though I do believe it. It would have been cutting edge technology at the time, and the higher thermal burden on the filaments would absolutely call for a more robust tube. I guess the original appeal of the AC/DC set would have had to have been mass production of a singular design for all.

Just comes to show, no one person is an expert on anything!