[78-L] 78 grove spacing

[Jeff Sultanof]

Thank you, Malcolm. I just downloaded it.

Jeff Sultanof

On Thu, Aug 15, 2019 at 6:23 AM Kristjan Saag <saag at telia.com.invalid>
wrote:

>
>  From September 1950 Deutsche Grammophon's Archive series 78's had
> variable pitch/ variable groove spacing, thus almost double playtime.
> Polydor also used the technique for some of their 78's.
> The technique, with control amplifiers connected to the tape machine, is
> described on pages 649-650 in the Audio Cyclopedia.
>
> Kristjan
>
>
> On 2019-08-15 01:59, ron at fial.com.invalid wrote:
> > I saw no activity, so I was just testing that everything was OK on the
> > 78-L server. Here is a question. I know that grove excursion must be
> > limited to keep loud low-frequency passages from breaking to an
> > adjacent grove when cutting a record. This can be done with level
> > limiter, volume compression and (egads) clipping and low frequency
> > limiting. I recall that in the vinyl era there were automatic means to
> > create greater grove spacing for loud passages. I could be mistaken.
> > What methods were used for 78-RPM records. Was someone riding the
> > volume control and watching the VU meter, when that came along. What
> > technologies if any were used and when did they come along. There may
> > have been allowance for the grove getting wider with many playings,
> > right? I suppose a microscope used on acoustic and early electricals
> > would reveal much. Any one here already know? Ron Fial
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>
>
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