The Generator on the Mi Amigo, ran at 60hz - to suit the USA Transmitters - in those days, the tape recorder would have a synchronous motor, designed for 50hz - but it would work on a 60hz supply, but run a bit fast That's what I suspect anyway. The "Storm Tape" may have been recorded on land, on a 50hz recorder.
For those that want to hear the storm tape recording at the right speed, there are settings within Windows media player & other players, to lower the pitch. In my opening post, that one has been "doctored" (The last 20 min recording)