[78-L] Glass versus Vinyl

[David Lennick]

What do we know about solid vinyl discs used for instantaneous cutting in the 
50s (and earlier?)? One radio station in Nova Scotia seems to have used them, 
since a couple of Don Messer's recordings issued in an 80s compilation are 
taken from them, and I was shown discs like this when I asked a small "record 
your voice" outfit in a record store in Toronto in 1958.

The CBC seems to have had to use glass discs before April 1941..maybe because 
we were in the war that much earlier?

dl

On 1/6/2011 12:14 PM, Michael Biel wrote:
> I am not sure that the original questioner completely understood the
> difference between how a lacquer-coated disc and a vinyl pressing is
> made.  Lacquer discs are individually cut with a sharp stylus and
> material is removed to form the groove.  Glass was used as a supporting
> base between April 1941 and mid-1945 to replace aluminum which was a
> strategic war material.  Steel and paper fibre was also used.  Vinyl
> discs, like shellac and other similar materials, are pressed in multiple
> quantities in a hydraulic press from metal negative stampers.
>
> So the question of glass vs vinyl makes no real sense.  Now if you want
> to ask about the use of lacquer coated discs for instantaneous recording
> vs. the use of solid vinyl blanks for instantaneous recording -- such as
> what Lennick mentioned as dub-plates -- now we have a question.  Vinyl
> can be either embossed or cut.  In the Victor pre-grooved discs and in
> dictating machines like SoundScriber, Gray Autograph, Edison Diamond
> Disc, and Dictabelts, the vinyl was embossed.  Because no material was
> removed the grooves are not necessarily permanent and the plastic might
> have a memory and return at least slightly if not completely to its
> original shape.  In any evcent, the plastic had a resistance and did not
> give a full fidelity recording.  When vinyl is used for cutting it is
> harder to cut than is the soft lacquer.  There were some German discs
> that were made of vinyl during the war years that were cut -- Decelith
> is one example -- but they are not as high quality as a lacquer coated
> disc.
>
> For high quality disc mastering, lacquer coated discs are still used,
> and the supporting base is aluminum.  The only quality alternative is
> DMM Direct Metal Mastering which cuts a groove on a copper-coated disc
> using a high-frequency bias to enable the cutting of the metal.
> (Uncoated aluminum discs in the early 30s were embossed, not cut.)
> Vinyl Dub-Plates are not high quality enough to be used for professional
> mastering.
>
> Now if the question is breakable shellac pressings vs. unbreakable vinyl
> pressings, that also is a completely different matter.  Vinyl discs
> would be ruined on heavy playback machines like acoustical wind-ups, and
> the material was initially more expensive than the shellac compounds.
> When lightweight pick-ups became common it was more used -- starting
> mainly with mass-produced pressed broadcast transcriptions in the 30s.
>
> Mike Biel  mbiel at mbiel.com
>
> On 1/6/2011 11:08 AM, David Lennick wrote:
>> Vinyl, Victrolac, whatever, was also used for pre-grooved discs made by Victor
>> in the 30s and 40s. The playback CAN be of decent quality if you can find a
>> stylus wide enough..these weren't intended for professional or broadcast use.
>> Some other plastics like celluloid were used for home recordings..again,
>> nowhere near professional quality. I know of one instance where fiber based
>> Presto discs (16 inch) were used for a program to be shipped and broadcast
>> overseas by the CBC, and presumably they just didn't want to risk breaking
>> it..it was a Gracie Fields Christmas program recorded in Vancouver but to be
>> broadcast via short wave from Ottawa. The quality 50 years later was excellent.
>>
>> dl
>>
>> On 1/6/2011 10:35 AM, David Lennick wrote:
>>> Two things are being intermixed here..glass replaced aluminum when it became
>>> unavailable during the war. Vinyl was used for pressings, and rarely for discs
>>> sold to consumers until it was economically feasible to use it and pickups were
>>> lighter by the mid 40s. I've seen vinyl soft cuts from the fifties and I think
>>> that's what's used today for "dub plates" but can anyone comment on the quality
>>> of the 50s vinyl soft cuts? Noise level? Frequency range? Durability?
>>>
>>> dl
>>>
>>> On 1/6/2011 10:29 AM, marimbamoods at comcast.net wrote:
>>>>
>>>> just wondering - why were lacquer-coated glass-based transcription discs used well after the introduction of vinyl?
>>>>
>>>>
>>>> i recently encountered a damaged glass-based disc from 1945, though vinyl discs were in use as early as ten or more years prior to that. given the fragility of the glass type, why were those manufactured at a time when vinyl was readily available?
>>>>
>>>>
>>>> are the lacquer-coated surfaces somehow superior to the vinyl surfaces for fidelity or noise levels? that does not seem likely given the smoothness of vinyl, which continued in use for a half-century after its' introduction.
>>>>
>>>>
>>>> so, why deal with the delicate handling issues of glass-based discs when hassle-free vinyl was already in use?
>>>>
>>>>
>>>> best, david harvey