The two Ellington records are something completely different, or rather
the intent was different. They were long-playing 33 1/3 RPM "Electrical
Transcriptions" for home consumption, and the reason there were two
microphones, amplifiers, cutters, and waxes on this two-disc session was
because RCA was running tests on an electrical recording system they
were developing, to compare results with an identical setup using
Western Electric equipment, on which they were still paying hefty royalties.
The tests evidently showed there was work to be done, because the RCA
system wasn't phased in for three more years. Discs made with the
Western Electric equipment have the letters "VE" in an ellipse, whereas
from about 1934 onward they appear in a diamond, signifying RCA equipment.
On 8/30/2014 12:06, Clark Johnsen wrote:
> Best I recall, "accidental stereo" was discovered, quite accidentally, by
> Brad Kay of Venice, California. Soon after the announcement was made I
> visited him there and heard for myself some *pretty good* stereo from 1927
> and yes it was Duke Ellington, inter alia.
> But that was from the electrical era, when just as in the acoustical a
> second master was made for backup, albeit with another microphone. It's my
> understanding that often enough actual discs were issued from the "backup"
> and thus are locatable even today. You just have to know what to look for.