--- On Mon, 5/18/09, Steven Smolian <[log in to unmask]> wrote:
> If memory serves, the smaller 1930s
> diameter was required to clear the jukebox mechanisms.
The only major prewar mechanism for which the record
diameter was a major consideration was AMI's which
used a gripper-arm to transfer the record from the
magazine to the turntable (this record changer was
intoduced in 1927 and this same type of transfer
arm is still used on Rowe/AMI's CD jukeboxes to this
day). The transfer arm will clear a nominal 10-1/4"
in its fully open position, but of course the design
assumes enough clearance for the record magazine to
freely move back and forth through the gap of the open
arm. The other major manufacturers, Seeburg, Wurlitzer
and Rock-Ola, all used horizontally moving record
trays to move the record over a rising turntable
in their prewar record changers, and in those the
center hole was a more immediate limiting factor
than the outside diameter.