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Welcome Licorice Pizza (LP) lovers! Setup guides and Vinyl FAQ.

RE: So, why 16.66, 33.33, 45, 78 rpm?

Others may have more definitive information but here's a rough explanation.

It all started with no standard speed, but somewhere between 60-70rpm and 90rpm depending on company and the accuracy of the cutting engineer's calibrations.

By the mid twenties the nominal speed had settled to 78 or 80rpm and soon just 78. I think this has to do with gearing ratios and power supplies of the time.

78 isn't 78 really as once electricity raised it's ugly head, in 60hz power supplies (US etc) it's 78.26rpm and 50hz (EU etc) 77.92rpm.

33⅓ was used from about 1930 for Long play records issued by RCA and radio transcriptions and, again, I think it relates to mains frequency and gearing. It's the same internationally. It was used by Columbia for mastering from about 1939 in preparation for the LP we know and love today.

In 1949/50 RCA wanted nothing to do with the new Columbia LP and launched their own new record, the 7" 45rpm with a large hole for their fast auto changer. I don't know why they settled on 45 other than it wasn't 33 and compatible with the Columbia system. It even had different EQ.

I don't know when 16⅔rpm came into use, post WW2 possibly and mainly for talking books for the blind. Some music LP were issued, I have a Vox one with 4 complete violin concertos on it.

OK guys anything wrong or has been missed?




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