On Wed, 25 Oct 2023 21:10:39 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

>Scott <newsgroups@gefion.myzen.co.uk> wrote:
>
>> On Wed, 25 Oct 2023 17:50:38 +0100, liz@poppyrecords.invalid.invalid
>> (Liz Tuddenham) wrote:
>>
>> >Brian Gaff <brian1gaff@gmail.com> wrote:
>> >
>> >> Perhaps the noise should be on R3? They have always liked their
>> >> experimental music. Theme of an Autumn evening played by Angle grinder
>> >> wellder and old sofa.
>> >
>> >Memories of the Shagbut, Minnikin and Flemish Clacket.
>> >
>> >If you think R3 was odd, you should have heard some of the programmes on
>> >Resonance F.M. My programme, where I D.J.ed 78s. barrel pianos and wax
>> >cylinders, in the manner of a 1950s BBC announcer, was positively
>> >mainstream by comparison.
>>
>> Is there any link to your DJ'ing skills?
>
>Search for "Life Before Vinyl". I believe you can still download the
>programmes from Resonance F.M. but if you can't, follow this link...
>
>http://www.poppyrecords.co.uk/lifebeforevinyl/P01.htm
>
>Directly underneath where it says :Programme 1" is a dot, click on that
>for an MP3 download. Similarly on all the other programme pages.
>
Thanks. I'll listen in detail later but the first track sounds like a
78 rpm shellac? Were all 78s shellac or could other materials be used?

Scott <newsgroups@gefion.myzen.co.uk> wrote:

> On Wed, 25 Oct 2023 21:10:39 +0100, liz@poppyrecords.invalid.invalid
> (Liz Tuddenham) wrote:
>
> >Scott <newsgroups@gefion.myzen.co.uk> wrote:
> >
> >> On Wed, 25 Oct 2023 17:50:38 +0100, liz@poppyrecords.invalid.invalid
> >> (Liz Tuddenham) wrote:
> >>
> >> >Brian Gaff <brian1gaff@gmail.com> wrote:
> >> >
> >> >> Perhaps the noise should be on R3? They have always liked their
> >> >> experimental music. Theme of an Autumn evening played by Angle grinder
> >> >> wellder and old sofa.
> >> >
> >> >Memories of the Shagbut, Minnikin and Flemish Clacket.
> >> >
> >> >If you think R3 was odd, you should have heard some of the programmes on
> >> >Resonance F.M. My programme, where I D.J.ed 78s. barrel pianos and wax
> >> >cylinders, in the manner of a 1950s BBC announcer, was positively
> >> >mainstream by comparison.
> >>
> >> Is there any link to your DJ'ing skills?
> >
> >Search for "Life Before Vinyl". I believe you can still download the
> >programmes from Resonance F.M. but if you can't, follow this link...
> >
> >http://www.poppyrecords.co.uk/lifebeforevinyl/P01.htm
> >
> >Directly underneath where it says :Programme 1" is a dot, click on that
> >for an MP3 download. Similarly on all the other programme pages.
> >
> Thanks. I'll listen in detail later but the first track sounds like a
> 78 rpm shellac?

The title track is a composite of a record firstly played on a clockwork
gramophone, then merging into an electrical transcription of the same
record. It is poor quality and well-worn 78 rpm shellac from a very
cheap manufacturer.

>Were all 78s shellac or could other materials be used?

By far the greatest number were pressed on 'Shellac', or 'Solid stock',
which is mostly slate dust and other abrasives held together with a
binder of shellac. In the early days the groove profile wasn't clearly
specified (the very first ones were etched with acid) so the needle
point had to be ground down to fit the groove on each individual record.

An astounding variety of other materials were tried at various times,
ranging from solid chocolate to cellophane on cardboard. One of the
most successful 'laminate' records used a core of coarse rubbish
(including cotton flock) with surface layers of extremely finely-ground
'shellac' compound for the grooves. 'Direct cut' discs were cellulose
nitrate varnish on an aluminium base, but scarcity of aluminium during
WWII led to galvanised steel and glass being used as substitutes.

Vinyl was too expensive to use before the days of microgroove records,
but the very last 78s were pressed on vinyl because the machinery to
make and press solid stock had become uneconomical for the small
quantities needed.

--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

On Thu, 26 Oct 2023 10:39:55 +0100, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:

>Scott <newsgroups@gefion.myzen.co.uk> wrote:
>
>> On Wed, 25 Oct 2023 21:10:39 +0100, liz@poppyrecords.invalid.invalid
>> (Liz Tuddenham) wrote:
>>
>> >Scott <newsgroups@gefion.myzen.co.uk> wrote:
>> >
>> >> On Wed, 25 Oct 2023 17:50:38 +0100, liz@poppyrecords.invalid.invalid
>> >> (Liz Tuddenham) wrote:
>> >>
>> >> >Brian Gaff <brian1gaff@gmail.com> wrote:
>> >> >
>> >> >> Perhaps the noise should be on R3? They have always liked their
>> >> >> experimental music. Theme of an Autumn evening played by Angle grinder
>> >> >> wellder and old sofa.
>> >> >
>> >> >Memories of the Shagbut, Minnikin and Flemish Clacket.
>> >> >
>> >> >If you think R3 was odd, you should have heard some of the programmes on
>> >> >Resonance F.M. My programme, where I D.J.ed 78s. barrel pianos and wax
>> >> >cylinders, in the manner of a 1950s BBC announcer, was positively
>> >> >mainstream by comparison.
>> >>
>> >> Is there any link to your DJ'ing skills?
>> >
>> >Search for "Life Before Vinyl". I believe you can still download the
>> >programmes from Resonance F.M. but if you can't, follow this link...
>> >
>> >http://www.poppyrecords.co.uk/lifebeforevinyl/P01.htm
>> >
>> >Directly underneath where it says :Programme 1" is a dot, click on that
>> >for an MP3 download. Similarly on all the other programme pages.
>> >
>> Thanks. I'll listen in detail later but the first track sounds like a
>> 78 rpm shellac?
>
>The title track is a composite of a record firstly played on a clockwork
>gramophone, then merging into an electrical transcription of the same
>record. It is poor quality and well-worn 78 rpm shellac from a very
>cheap manufacturer.
>
>
>>Were all 78s shellac or could other materials be used?
>
>By far the greatest number were pressed on 'Shellac', or 'Solid stock',
>which is mostly slate dust and other abrasives held together with a
>binder of shellac. In the early days the groove profile wasn't clearly
>specified (the very first ones were etched with acid) so the needle
>point had to be ground down to fit the groove on each individual record.
>
>An astounding variety of other materials were tried at various times,
>ranging from solid chocolate to cellophane on cardboard. One of the
>most successful 'laminate' records used a core of coarse rubbish
>(including cotton flock) with surface layers of extremely finely-ground
>'shellac' compound for the grooves. 'Direct cut' discs were cellulose
>nitrate varnish on an aluminium base, but scarcity of aluminium during
>WWII led to galvanised steel and glass being used as substitutes.
>
>Vinyl was too expensive to use before the days of microgroove records,
>but the very last 78s were pressed on vinyl because the machinery to
>make and press solid stock had become uneconomical for the small
>quantities needed.

Thanks. The last paragraph is what I wondered. My grandfather had a 78
rpm turntable and I *thought* I had seen a vinyl disc (but it was a
very long time ago). My parents said you had to replace the stylus
after every play. Is this correct?

In article <3bfkjilkftc74jt2a7i3n85c5575ijmc7t@4ax.com>,
Scott <newsgroups@gefion.myzen.co.uk> wrote:
> On Thu, 26 Oct 2023 10:39:55 +0100, liz@poppyrecords.invalid.invalid
> (Liz Tuddenham) wrote:

> >Scott <newsgroups@gefion.myzen.co.uk> wrote:
> >
> >> On Wed, 25 Oct 2023 21:10:39 +0100, liz@poppyrecords.invalid.invalid
> >> (Liz Tuddenham) wrote:
> >>
> >> >Scott <newsgroups@gefion.myzen.co.uk> wrote:
> >> >
> >> >> On Wed, 25 Oct 2023 17:50:38 +0100, liz@poppyrecords.invalid.invalid
> >> >> (Liz Tuddenham) wrote:
> >> >>
> >> >> >Brian Gaff <brian1gaff@gmail.com> wrote:
> >> >> >
> >> >> >> Perhaps the noise should be on R3? They have always liked their
> >> >> >> experimental music. Theme of an Autumn evening played by Angle grinder
> >> >> >> wellder and old sofa.
> >> >> >
> >> >> >Memories of the Shagbut, Minnikin and Flemish Clacket.
> >> >> >
> >> >> >If you think R3 was odd, you should have heard some of the programmes on
> >> >> >Resonance F.M. My programme, where I D.J.ed 78s. barrel pianos and wax
> >> >> >cylinders, in the manner of a 1950s BBC announcer, was positively
> >> >> >mainstream by comparison.
> >> >>
> >> >> Is there any link to your DJ'ing skills?
> >> >
> >> >Search for "Life Before Vinyl". I believe you can still download the
> >> >programmes from Resonance F.M. but if you can't, follow this link...
> >> >
> >> >http://www.poppyrecords.co.uk/lifebeforevinyl/P01.htm
> >> >
> >> >Directly underneath where it says :Programme 1" is a dot, click on that
> >> >for an MP3 download. Similarly on all the other programme pages.
> >> >
> >> Thanks. I'll listen in detail later but the first track sounds like a
> >> 78 rpm shellac?
> >
> >The title track is a composite of a record firstly played on a clockwork
> >gramophone, then merging into an electrical transcription of the same
> >record. It is poor quality and well-worn 78 rpm shellac from a very
> >cheap manufacturer.
> >
> >
> >>Were all 78s shellac or could other materials be used?
> >
> >By far the greatest number were pressed on 'Shellac', or 'Solid stock',
> >which is mostly slate dust and other abrasives held together with a
> >binder of shellac. In the early days the groove profile wasn't clearly
> >specified (the very first ones were etched with acid) so the needle
> >point had to be ground down to fit the groove on each individual record.
> >
> >An astounding variety of other materials were tried at various times,
> >ranging from solid chocolate to cellophane on cardboard. One of the
> >most successful 'laminate' records used a core of coarse rubbish
> >(including cotton flock) with surface layers of extremely finely-ground
> >'shellac' compound for the grooves. 'Direct cut' discs were cellulose
> >nitrate varnish on an aluminium base, but scarcity of aluminium during
> >WWII led to galvanised steel and glass being used as substitutes.
> >
> >Vinyl was too expensive to use before the days of microgroove records,
> >but the very last 78s were pressed on vinyl because the machinery to
> >make and press solid stock had become uneconomical for the small
> >quantities needed.

> Thanks. The last paragraph is what I wondered. My grandfather had a 78
> rpm turntable and I *thought* I had seen a vinyl disc (but it was a
> very long time ago). My parents said you had to replace the stylus
> after every play. Is this correct?

My father didn't, he used steel ones, but there were non-metalic ones that
only lasted one playing. They were called needles in those days.
Listen to: Flanders and Swann's "A Song of Reproduction"

--
from KT24 in Surrey, England - sent from my RISC OS 4té²
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

Scott <newsgroups@gefion.myzen.co.uk> wrote:

> On Thu, 26 Oct 2023 10:39:55 +0100, liz@poppyrecords.invalid.invalid
> (Liz Tuddenham) wrote:
[...]
> >>Were all 78s shellac or could other materials be used?
> >
> >By far the greatest number were pressed on 'Shellac', or 'Solid stock',
> >which is mostly slate dust and other abrasives held together with a
> >binder of shellac. In the early days the groove profile wasn't clearly
> >specified (the very first ones were etched with acid) so the needle
> >point had to be ground down to fit the groove on each individual record.
> >
> >An astounding variety of other materials were tried at various times,
> >ranging from solid chocolate to cellophane on cardboard. One of the
> >most successful 'laminate' records used a core of coarse rubbish
> >(including cotton flock) with surface layers of extremely finely-ground
> >'shellac' compound for the grooves. 'Direct cut' discs were cellulose
> >nitrate varnish on an aluminium base, but scarcity of aluminium during
> >WWII led to galvanised steel and glass being used as substitutes.
> >
> >Vinyl was too expensive to use before the days of microgroove records,
> >but the very last 78s were pressed on vinyl because the machinery to
> >make and press solid stock had become uneconomical for the small
> >quantities needed.
>
> Thanks. The last paragraph is what I wondered. My grandfather had a 78
> rpm turntable and I *thought* I had seen a vinyl disc (but it was a
> very long time ago). My parents said you had to replace the stylus
> after every play. Is this correct?

If you were lucky enough to find a vinyl 78, you would play it with a
lightweight sapphire or diamond stylus. These were 'permanant' styli
and took a long while to wear out. The same stylus would play 'shellac'
records but, because it didn't wear to fit the groove section, it
didn't give good results on older records (later records had
standardised grooves that suited the stylus).

Most 78s are cut with 'coarse' grooves whereas later records (45 and
33+1/3 rpm) are 'microgroove'. Two different styli are needed and these
were often arranged on opposite sides of the cartridge, which could be
turned over to select the required stylus. Another system had them on
opposite sides of a lightweight bar which could be rotated. Philps had
them side by side, so the head was rocked to select them, Decca had two
completely separate plug-in heads and most later American manufacturers
had little plug-in carriers that had to be interchanged. A whole range
of custom stylus sizes is available for playing older 78s correctly, but
they are individually made and very expensive.

Needles were available in steel, fibre (bamboo) or thorn. Because they
wore down, they had to be replaced at each playing. A steel needle with
'flats' worn into it by one groove shape could do a lot of damage if it
was re-used in a groove of a different shape. You were lucky to get a
fibre or thorn to last more than 4 minutes, so you had to either keep
replacing them or sharpen them between records with a little gadget.
Some electrical pickups that used needles relied on the needle acting as
a magnetic armature - there are many stories of operators caught out
when they accidentally used thorns or brass tacks.

There were discs made of 'filled vinyl', which was vinyl with a lot of
abrasive in it. These were used for broadcast transcription, for
distributing programmes to remote transmitters and the internal
broadcasting systems of military bases. The advantage was that they
were lighter than shellac pressings for air freight and almost
unbreakable, but could still be played on existing equipment with a
needle in an electrical pickup. Some of them were 16" diameter, so you
would have difficulty playing them on domestic equipment.

For early film soundtracks there were 16" solid-stock discs with
vertical modulation of the groove. They started at the centre and
played outwards, with a little pit at the beginning, which the operator
placed the needle in. Having positively lined up the disc on the
turntable, he lined up the film in the projector to a marked frame on
the leader and then coupled the two machines together with a clutch.
From then on, they were supposed to stay in synch. Because the discs
were so large, they could be recorded at 33+1/3 rpm to give a reasonable
surface speed without too much loss of sound quality and would last for
one reel of the film.

--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

In message <1qj7e6f.prqz9x1rl7osgN%liz@poppyrecords.invalid.invalid> at
Thu, 26 Oct 2023 10:39:55, Liz Tuddenham
<liz@poppyrecords.invalid.invalid> writes
[]
>An astounding variety of other materials were tried at various times,
>ranging from solid chocolate to cellophane on cardboard. One of the
>most successful 'laminate' records used a core of coarse rubbish
>(including cotton flock) with surface layers of extremely finely-ground
>'shellac' compound for the grooves. 'Direct cut' discs were cellulose
>nitrate varnish on an aluminium base, but scarcity of aluminium during
>WWII led to galvanised steel and glass being used as substitutes.

Not to mention, presumably, problems with them exploding if not
carefully handled, like old cinema film of the same base!

I remember reading - in the 1980s I think, it was in something I had
access to at work (Journal of the Aeronautical society maybe? That's
where I found one of the original Nyquist papers) - a series of papers
on using light (lasers IIRR) to read some metal discs, where rust had
rendered them unplayable conventionally. Whether they were metal core
with a coating or just metal, I forget. They had been used to record
one-off material pre-war in Japan - can't remember whether it was folk
music or spoken history. The work was being done in Japan, as it was
their heritage. (I do remember some laser record players - in the '90s
were they? - that were generally not well reviewed: I think they cost
about 7000 quid then, and didn't produce remarkable results. I don't
think they had anything to do with the papers I found.)
>
>Vinyl was too expensive to use before the days of microgroove records,
>but the very last 78s were pressed on vinyl because the machinery to
>make and press solid stock had become uneconomical for the small
>quantities needed.
>
>
I remember at the time of the film about Josef Locke [the - Irish, I
think - singer] (was it called "hear my song"? That was certainly the
main song), there was a reissue of his 78 of it, with much comment in
the media that many of those buying it probably didn't have anything to
play it on. I suspect that was vinyl. 1990s was it? (I could look on
IMDB.)
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

"Purgamentum init, exit purgamentum." Translation: "Garbage in, garbage out."

On 26/10/2023 09:50, Liz Tuddenham wrote:
> tony sayer <tony@bancom.co.uk> wrote:
>
>> In article <1qj437t.1541ev71j14zi8N%liz@poppyrecords.invalid.invalid>,
>> Liz Tuddenham <liz@poppyrecords.invalid.invalid> scribeth thus
> [...]
>>> R4 is back to normal now but the unmodulated carrier is still there at
>>> 100.16 Mc/s.
>>>
>>>
>> You could try mailing Ofcom but...
>>
>> Or Arqiva?..
>>
>>
>> radio@arqiva.com
>>
>>
>> They usually take sensible complaints seriously..
>>
>> Be a waste of time contacting the BBC :-(
>
> The 100.16 Mc/s signal is now carrying Classic F.M..
>
>
I hope it wasn't 101.16.
100.2 MHz is the frequency of Classic FM from the Bath relay

J. P. Gilliver <G6JPG@255soft.uk> wrote:

> In message <1qj7e6f.prqz9x1rl7osgN%liz@poppyrecords.invalid.invalid> at
> Thu, 26 Oct 2023 10:39:55, Liz Tuddenham
> <liz@poppyrecords.invalid.invalid> writes
> []
> >An astounding variety of other materials were tried at various times,
> >ranging from solid chocolate to cellophane on cardboard. One of the
> >most successful 'laminate' records used a core of coarse rubbish
> >(including cotton flock) with surface layers of extremely finely-ground
> >'shellac' compound for the grooves. 'Direct cut' discs were cellulose
> >nitrate varnish on an aluminium base, but scarcity of aluminium during
> >WWII led to galvanised steel and glass being used as substitutes.
>
> Not to mention, presumably, problems with them exploding if not
> carefully handled, like old cinema film of the same base!

It is fun when the discs have started to develop 'mud cracks' and are
becoming contact-sensitive. I play them under a coating of water, as
high-speed contact with a diamond stylus could produce louder noises in
the room than those that were recorded on the disc. :-)

>
> I remember reading - in the 1980s I think, it was in something I had
> access to at work (Journal of the Aeronautical society maybe? That's
> where I found one of the original Nyquist papers) - a series of papers
> on using light (lasers IIRR) to read some metal discs, where rust had
> rendered them unplayable conventionally. Whether they were metal core
> with a coating or just metal, I forget. They had been used to record
> one-off material pre-war in Japan - can't remember whether it was folk
> music or spoken history. The work was being done in Japan, as it was
> their heritage. (I do remember some laser record players - in the '90s
> were they? - that were generally not well reviewed: I think they cost
> about 7000 quid then, and didn't produce remarkable results. I don't
> think they had anything to do with the papers I found.)

I attended a demonstraton of one at the National Sound Archive, where it
was being touted as the answer to an archivist's prayer. It refused to
acknowledge the presence of a test disc because the reflectivity was
wrong. It turns out that the designer hadn't been told that 98% of all
the material an archival player would have to deal with was pressed on
'shellac' not on vinyl -- the rest was on nitrate.

The next stumbling block was that it could only play 12" or 7" records;
there were very few 7" 78s ever made and most of the discs in the
archive were 10". It appears that the archiving specialist also hadn't
thought to include 60, 78, 80, 90 rpm or any of the other common speeds
that are needed for archival material.

Finally it played an L.P. rather unremarkably except for the high noise
level. It turned out that the discs had to be scrubbed absolutely clean
before they could be played in a 'contactless' player because every bit
of dirt was played as a solid object, instead of being swept out of the
way by a stylus.

The technical experts at the Sound Archive tried to be as helpful to the
salesman as they possibly could, but it soon became apparent that the
machine was totally useless.

--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

Mark Carver <mark@invalid.com> wrote:

> On 26/10/2023 09:50, Liz Tuddenham wrote:
> > tony sayer <tony@bancom.co.uk> wrote:
> >
> >> In article <1qj437t.1541ev71j14zi8N%liz@poppyrecords.invalid.invalid>,
> >> Liz Tuddenham <liz@poppyrecords.invalid.invalid> scribeth thus
> > [...]
> >>> R4 is back to normal now but the unmodulated carrier is still there at
> >>> 100.16 Mc/s.
> >>>
> >>>
> >> You could try mailing Ofcom but...
> >>
> >> Or Arqiva?..
> >>
> >>
> >> radio@arqiva.com
> >>
> >>
> >> They usually take sensible complaints seriously..
> >>
> >> Be a waste of time contacting the BBC :-(
> >
> > The 100.16 Mc/s signal is now carrying Classic F.M..
> >
> >
> I hope it wasn't 101.16.
> 100.2 MHz is the frequency of Classic FM from the Bath relay

It was most likely an error in my measuring setup. I tuned-in the
signal with an Eddystone 770R and centred the trace on the oscilloscope
screen of an EP14 panoramic adaptor. Then I adjusted a Marconi TF2016A
signal generator until its carrier appeared in the centre of the trace.
Finally I measured the frequency of the signal generator with a Racal
9913 frequency meter.

The crystal oven in the frequency meter has been running non-stop for
several months, so that wouldn't have drifted. The most likely source
of error was inaccurately superimposing the two traces on the
oscilloscope screen, but because I was a bit surprised that the
frequency wasn't a nice round number, I did check it twice.

--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

On 26/10/2023 13:23, Liz Tuddenham wrote:
> Most 78s are cut with 'coarse' grooves whereas later records (45 and
> 33+1/3 rpm) are 'microgroove'. Two different styli are needed and these
> were often arranged on opposite sides of the cartridge, which could be
> turned over to select the required stylus.

The problem came with record decks that didn't have a rotatable pair of
styluses. My dad's B&O deck was like this - it only had a microgroove
33/45 rpm stylus, even though it was capable of turning at 78 rpm as
well. I imagine a lot of "noisy, scratchy" 78 discs would actually be
less noisy if played with a proper 78 rpm coarser-groove stylus. I
suppose if he'd had a lot of 78s that we wanted to play, he'd have
bought a 78 stylus/cartridge as well.

> There were discs made of 'filled vinyl', which was vinyl with a lot of
> abrasive in it. These were used for broadcast transcription, for
> distributing programmes to remote transmitters and the internal
> broadcasting systems of military bases. The advantage was that they
> were lighter than shellac pressings for air freight and almost
> unbreakable, but could still be played on existing equipment with a
> needle in an electrical pickup. Some of them were 16" diameter, so you
> would have difficulty playing them on domestic equipment.

My grandpa was a headmaster who was very interested in steam locomotives
and railways in general. Some time in the 1940s or 50s, he was asked to
present a series of programmes about railways, aimed at children, on
Children's Hour. We have a shellac-on-aluminium disc of one of his
programmes, probably given to him by the BBC so he could listen to his
programme afterwards. It is notorious in our family because the BBC
asked him to tone down his fairly mild West Riding of Yorkshire accent,
which offended him greatly so he hammed it up and put on an exaggerated
Bob Danvers-Walker (or Mr Cholmondley-Warner) accent, using vowels that
were unknown to anyone outside the Home Counties. It is obvious on the
record that it is Grandpa's voice, but he is putting on a very obviously
faked accent: "end sew pritty soon teh smoake is camming aout of the
chimney laike a ballett fram a gan" ("and so pretty soon the smoke is
coming out of the chimney like a bullet from a gun").

NY <me@privacy.net> wrote:

[....]

>I imagine a lot of "noisy, scratchy" 78 discs would actually
>be less noisy if played with a proper 78 rpm coarser-groove stylus.

Yes, and the distortion would also be a lot less. A too-small stylus
tip is going to wander around and won't follow the path of the original
cutter tip.

[...]

>We have a shellac-on-aluminium disc of one of his
> programmes, probably given to him by the BBC so he could listen to his
> programme afterwards.

It won't be shellac, it will be cellulose nitrate. Shellac mixture is
only suitable for pressings, where heat and pressure form the grooves.

They called those one-off discs 'Acetates' because it sounded less
scary, but a groove couldn't be cut in acetate, which tore in a random
manner and made a lot of noise. Nitrate could be cut smoothly and is
still used for mastering L.P.s, despite its other disadvantages.

Acetate could be used to make embossed recordings, but not on a normal
disc cutter. It needed a lot of pressure on the cutting tip which meant
a more powerful motor was needed to drive the disc. The high frequency
response and maximum slew-rate were worse because of the rounded shape
of the embosser tip. Embossing was used for unskilled or unattended
operation, or where a swarf thread would be an embarassment, such as
dictating machines or broadcast loggers.

--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

On Friday, 27 October 2023 at 10:02:49 UTC+1, NY wrote:
Some of them were 16" diameter, so you
> > would have difficulty playing them on domestic equipment.

Jig saw.
Bill

wrightsaerials@aol.com <wrightsaerials@f2s.com> wrote:

> On Friday, 27 October 2023 at 10:02:49 UTC+1, NY wrote:
> Some of them were 16" diameter, so you
> > > would have difficulty playing them on domestic equipment.
>
> Jig saw.

At an exhibition a few years ago, someone once brought along a 20"
Pathé disc for me to play. I had designed the player to accept 16"
discs without modification and the only thing preventing it from playing
20" discs was an end cheek supporting the rails of the parallel-tracking
mechanism.

Out with the screwdriver, off with the end cheek. The rails proved
sufficiently rigid for the parallel-tracking carrige to work, even
though they were cantilevered from the only remaining bracket at the
opposite end of the machine.

The next snag was the playing speed of 120 rpm. We overcame this by
playing the disc 'digitally' i.e. spinning it with a finger. The result
was of more interest in the historical domain than the musical one.

--
~ Liz Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

In message <1qjfn6m.1yf11mwimq8twN%liz@poppyrecords.invalid.invalid> at
Mon, 30 Oct 2023 21:29:39, Liz Tuddenham
<liz@poppyrecords.invalid.invalid> writes
[]
>At an exhibition a few years ago, someone once brought along a 20"
>Pathé disc for me to play. I had designed the player to accept 16"
>discs without modification and the only thing preventing it from playing
>20" discs was an end cheek supporting the rails of the parallel-tracking
>mechanism.
>
>Out with the screwdriver, off with the end cheek. The rails proved
>sufficiently rigid for the parallel-tracking carrige to work, even
>though they were cantilevered from the only remaining bracket at the
>opposite end of the machine.
>
>The next snag was the playing speed of 120 rpm. We overcame this by
>playing the disc 'digitally' i.e. spinning it with a finger. The result
>was of more interest in the historical domain than the musical one.
>
Not sure I'd want to have been in the vicinity of a 20" disc rotating at
120 RPM!

Back in the days of CD writers, you may remember they got faster and
faster - 4×, 8×, 10, 12, ... but peaked at around 48 or 50×; I did read
or hear somewhere that that limit was not so much a difficulty in making
the drives track that fast or processing (or writing with the laser) the
data that fast, but that it had been found that much above that, there
was a danger of the discs disintegrating, sending bits of plastic
flying. If you work out the rim speed - even at ×1, CDs spin at about
700 RPM at the start (inner) track down to about 400 at the end
(outside) - that sounds plausible: 50 × 400 = 20,000 RPM! (Much above
about 8-12× speed, CD drives didn't claim that speed factor throughout
the disc, going for constant angular velocity rather than linear.)
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

Sometimes you win, sometimes you learn.