barry hufker wrote:
Jack Mullin brought the first tape recorders (Magnetophon) to the U.S. American recorders were based on that.
effectively true, not quite totally true,
Jack Mullin brought the first tape recorders to the US that were used for later development of real commercial products, AEG showed the Magnetophone to GE and RCA around 1936, neither was interested. It was still DC bias at that time, AC bias was adopted during the war, see the article on Richard Hess's web page for that story.