Does anyone (else) remember the P connector? It was a predecessor to the
XL/XLR and was about an inch across with three pins on a right, not
equilateral, triangle. In the '70s I saw some in a 1930's school theater
(Pasadena CA) and a couple of years later in another old theater. Who made
them? When? Any photos? There is approximately zero info about them in
google, at least that I've been able to find.

Thanks,

z!