gregbogantz wrote:I suspect the change to 78.26 rpm was simply a nod to recent record industry convention. The latest electrical DDs recorded at 78 were released just a bit later than the Edison electrical phonographs, particularly the models C-1 and C-2 which were designed to play both DDs and lateral cut records. Adopting a consistent record speed made life easier for the player owner who didn't have to fuss with his speed control when changing from one type of disc to the other. Also, the adoption of the 78.26rpm speed is the result of using synchronous motors on the recording lathes operating on 60Hz AC mains power. This provided a stable cutting speed technology without the need for adjustment of the lathe. Synchronous motors in playback equipment were also becoming available at this time so that broadcast stations and other professional uses could be assured of correct speed playback.
That's an interesting comment, but I'll pick the nit that the needle cut discs and the very late DDs are are 78.8, slightly faster than the 78.26 syncronous motor "standard".
Do the C-1 and C-2 have speed controls? If not, precisely what speed do they play at (at 60 Hz)? I'm wondering if they clock out at around 79 so that "regular" 78s, needle cut Edisons, and Diamond Discs are all within 1 RPM.