[78-L] 17 1/2" transcription blanks

[Michael Biel]

On 7/29/2012 12:10 PM, David Weiner wrote:
>> And I just got several early RCA 45 7-inch master tests
>> that were cut on 10-inch blanks, dated December 1948.
>> When were the first 45s issued?   Dave Weiner

From: David Lennick <dlennick at sympatico.ca>
> February 1949, no? Interesting to note that several early
> RCA lps have D-(1949) prefixes, so they were obviously
> preparing to "join 'em" before 1950. dl

I can't get to my copies of the ledger sheets right now, but I think the
changeover in the speed of tests bringing the Madame X speed up from 40
to 45 RPM took place in 1943.  They were also making comparison
microgroove tests at 33 1/3 to show how much better 45 would be.  They
were usually using audio from the NBC broadcast lines.

Mike Biel  mbiel at mbiel.com  


>
> On 7/29/12 11:34 AM, "David Lennick"<dlennick at sympatico.ca> wrote:
>
>> These were required for cutting a 16-inch master from which pressings
>> were to
>> be made, leaving room to handle the disc when processing. Oversized discs
>> were also used for 12" and 10". I have a 14" disc that contains a 10-inch
>> 78RPM master, dating from about 1947. dl
>>
>> On 7/29/2012 11:27 AM, Dennis Flannigan wrote:
>>> Just noticed, my blank transcription discs are 17& 1/2 inches across.
>>> Is this a particular brand, and where they used differently than the 16"
>>> discs? Thank you, df