Well, Giff, my opinion is that the first electrical fade-out was done on a 1932 or '33 Duke Ellington Brunswick recording called "Steamboat Shuffle."
Sorry to say, I don't have it in my collection, but I do remember what it sounds like at the end: the band goes into a repeated paddlewheel-like riff, while the engineer in the control booth slowly turns the gain controls on the recording mikes down, to simulate the sound of a steamboat vanishing in the distance. This is all done with the most primitive vacuum-tube recording studio technology, but it works very well.
I used to own the original 78, but I sold it.
Too bad, because I've never come across the side again on any CD compilation of the Duke's music (and there are
hundreds).
Mr. Ellington was a very forward-looking individual; he also made some of the very first experimental— but
real— stereo extended-play microgroove recordings with RCA Victor in 1931-32. I do have those, and I'll be posting them as part of my current Early Swing series. Coming up next, as a matter of fact!
Generally speaking, I don't like fade-outs, I'd rather that the music comes to a definite conclusion. Would Beethoven, Brahms, or Tchaikovsky have used a fade-out, even if the technology had been available to them?
Naww...