[78-L] Approximating 78s age by physical characteristics

[David London]

> on others had lead outs but not all were eccentric. By 1933 I think
> most had eccentrics.
>
> Victor had a patented automatic brake system which included the eccentric groove. No one but Victor and its overseas affiliates were licensed to use it. In November of 1934 RCA announced that it would begin allowing other companies to use it. No reason was given but I assume there was some kind of quid pro quo with the jukebox industry. I've seen European discs from as late as 1937 with simple runouts.
> DJD
>

I was reading a page somewhere, about automatic changers and their 
history, and I think it was there that I also read that the spread of 
the eccentric groove to demands from the jukebox makers.  Sounds 
plausible, yes.