On 12/04/2022 08:17, Brian Gaff (Sofa) wrote:

> At one show there was something called a vinyl rescue system. Best part of
> 10,000 quid. It played the disc with lasers and could be adjusted so it
> played part of the grooves with no or minimal wear. The Japanese made it and
> it must have been the ultimate in the law of diminishing returns!

There is a video on the youtubes on that one. It didn't work
particularly well for the expense.

Perhaps, as we are now in the era of machine learning, someone could
have another go?

Don't need lasers. I'd just glue a weight compensated webcam with
microscope lens to the headshell, using the stylus to guide it. And do a
crazy amount of signal processing to turn the pictures into sound.

--
Adrian C

On Tue, 12 Apr 2022 11:24:56 +0100
Adrian Caspersz <email@here.invalid> wrote:

> Don't need lasers. I'd just glue a weight compensated webcam with
> microscope lens to the headshell, using the stylus to guide it. And do a
> crazy amount of signal processing to turn the pictures into sound.

I did once see a calculation that implied there were audible
features in the grooves that were smaller than the wavelength of blue light
and so below the resolution of a camera or laser pickup.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/

On 12/04/2022 08:17, Brian Gaff (Sofa) wrote:
> Plate glass? I'd have thought that would make things worse.
> 3M made a conductive foam mat and that did work quite well, as long as the
> turntable was metal.

You need to try it, then.
>
> The real problem though is that if they had made the record with some other
> substance it might not have been o bad, I was always amazed at how much
> charge could be generated in just playing a couple of tracks of an album,
> with what amounted to a tiny contact area.
> I remember some cartridges cam with a little carbon fibre brush on the
> front. Stanton, was it? Quite how the playing weight could ever be known
> with that on eluded me.
> At one show there was something called a vinyl rescue system. Best part of
> 10,000 quid. It played the disc with lasers and could be adjusted so it
> played part of the grooves with no or minimal wear. The Japanese made it and
> it must have been the ultimate in the law of diminishing returns!

I remember when it came out. I think it died very quickly, not because
of the cost, but because it 'played' every bit of dust the laser
encountered.

--
Rusty Hinge
To err is human. To really foul things up requires a computer and the BOFH.

On 12/04/2022 20:13, RustyHinge wrote:

> I remember when it came out. I think it died very quickly, not because
> of the cost, but because it 'played' every bit of dust the laser
> encountered.
>
That was the reason I heard for its failure. A stylus will "brush" some
small items of loose dirt away and ignore them that the laser left in place.

The only way a laser pickup could work well would be if the record was
"clean room" clean, and the "room" it was in also complied with the
standard.

--
Tciao for Now!

John.

On 12-Apr-22 14:19, Ahem A Rivet's Shot wrote:
> On Tue, 12 Apr 2022 11:24:56 +0100
> Adrian Caspersz <email@here.invalid> wrote:
>
>> Don't need lasers. I'd just glue a weight compensated webcam with
>> microscope lens to the headshell, using the stylus to guide it. And do a
>> crazy amount of signal processing to turn the pictures into sound.
>
> I did once see a calculation that implied there were audible
> features in the grooves that were smaller than the wavelength of blue light
> and so below the resolution of a camera or laser pickup.
>
Yet a mechanical tracking system was used to lay down that track, with
all its inherent limitations due to inertia & all that.

--
Sam Plusnet

On 12-Apr-22 20:19, John Williamson wrote:
> On 12/04/2022 20:13, RustyHinge wrote:
>
>> I remember when it came out. I think it died very quickly, not because
>> of the cost, but because it 'played' every bit of dust the laser
>>
> That was the reason I heard for its failure. A stylus will "brush" some
> small items of loose dirt away and ignore them that the laser left in
> place.
>
> The only way a laser pickup could work well would be if the record was
> "clean room" clean, and the "room" it was in also complied with the
> standard.
>
So you play each disc once, & copy it onto some other medium that
doesn't need this level of care?

--
Sam Plusnet

On 12/04/2022 08:35, Brian Gaff (Sofa) wrote:
> I think this discussion has moved out of my understanding!
>
> Imbalance of charges on the surfaces of materials has always interested me,
> it is almost a quantum effect.
> If you used an electroscope you could plainly see the variation in charges
> over records.
>
>
> I guess the ultimate ones were van der Graff generators, and windhurst
> machines. One used friction of a belt the other rotating discs.

Hmmm. I unforget Wimshurst machines. Big Bill Thorning used to stand on
an insulated platform, charge himself up, and poke his Roman nose at
some poor unsuspecting pupil's proboscis.

(Big Bill used to write well-received physics text-books)

One April 1st morning, when one of the physics labs was our form's
classroom, I sneaked into the store-room - I knew we were going to 'do'
the Wimshurst chamine, and twisted the other drive belt, so that both
discs would spin the same way. Poor Charlie Moss (Mayor of Wanstead and
Woodford, and our then physics teacher) moved the two brass balls (which
*should* hae had opposite charges), moved tehm closer and closer
together, then turning the handle furiously:no gurt long spark, no girt
short spark.

"I can't understend it," quoth he: "everything must be covered in a thin
layer of moiysture!"

Ever fter that when something failed, one heard the whisper: "everything
must be covered in a thin layer of moiysture!"

--
Rusty Hinge
To err is human. To really foul things up requires a computer and the BOFH.

On Tue, 12 Apr 2022 20:32:39 +0100
Sam Plusnet <not@home.com> wrote:

> Yet a mechanical tracking system was used to lay down that track, with
> all its inherent limitations due to inertia & all that.

When I was at fpubby we were taught that it would be forever
impossible to get an image of a single atom, within a few years the trick
had been managed several ways but the most amazing of them all is the
atomic force microscope which at the heart is a diamond stylus on a
cantilever tracking the outlines of atoms.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/

On Tue, 12 Apr 2022 21:50:41 +0100, Ahem A Rivet's Shot <steveo@eircom.net>
wrote:

> Wimshurst - we had an 18 plate one at fpubby until some safety
>inspectors found it. It could charge a brass doorknob up well enough to
>give a surprise to the next person opening the door DAMHIK.

Safety inspectors in a student lab didn't miss much. They did miss the
ergometer: a pushbike frame driving a generator, for the measurment of
electrical power. (Can be tricky, with AC and DC and waveforms and mulitple
phases volts and amps interfering with each others measurement.)

I saw on young man put out 750 Watts, generator power output (not input!) to
bananasockets and unshielded plugs on the leads. (Ran races, is what he said.)

Ouch, probably.

Thomas Prufer

Ahem A Rivet's Shot <steveo@eircom.net> wrote in
news:20220412215041.4d886828b60f91efd0c50d74@eircom.net:

> [1] There was a close call with sucking air into the gas pipes but
> that was averted by quick thinking as all the bunsen flames in the lab
> shrank.

A couple of lads in my school year got into the service ducts and swapped
over the gas and water. Expelled. One of them became a successful pop star
and (quick gurgle) is still touring.

--
Peter
-----

On 12/04/2022 20:34, Sam Plusnet wrote:
> On 12-Apr-22 20:19, John Williamson wrote:
>> The only way a laser pickup could work well would be if the record was
>> "clean room" clean, and the "room" it was in also complied with the
>> standard.
>>
> So you play each disc once, & copy it onto some other medium that
> doesn't need this level of care?
>
Which is what I have been doing ever since I stopped doing the mobile
disco thing, but using a stylus, not a laser.

--
Tciao for Now!

John.

That was what I was told, but of course they all knew a pleb like me would
not want to buy one!
I think it was good at avoiding the part that was worn. Or distorted.
There was a demo of the original Vinyl master of the Carpenters medley
including do you know the way to San Jose from the album Carpenters, which
had a nasty master defect that made a weird warbling whistle on playback,
They could define where the groove was carrying this signal and avoid it. I
got the impression that to work it had to be played very slowly to allow the
tracking to work reliably, then speeded up again and put on other media. Of
course it was pointless, as the CD and indeed the master tapes did not have
the problem as it was due to either cutting or pressing problems.
I did hear that some of the current Cylinders the BBC has have all been
played by laser as even a lightweight cart would further break up the wax
now its aging.

Brian

--

This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
briang1@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!
"Sam Plusnet" <not@home.com> wrote in message
news:Wuk5K.577972$7F2.152878@fx12.iad...
> On 12-Apr-22 20:19, John Williamson wrote:
>> On 12/04/2022 20:13, RustyHinge wrote:
>>
>>> I remember when it came out. I think it died very quickly, not because
>>> of the cost, but because it 'played' every bit of dust the laser
>>>
>> That was the reason I heard for its failure. A stylus will "brush" some
>> small items of loose dirt away and ignore them that the laser left in
>> place.
>>
>> The only way a laser pickup could work well would be if the record was
>> "clean room" clean, and the "room" it was in also complied with the
>> standard.
>>
> So you play each disc once, & copy it onto some other medium that doesn't
> need this level of care?
>
> --
> Sam Plusnet

On Wed, 13 Apr 2022 07:04:42 -0000 (UTC)
Peter <myshed@prune.org.uk> wrote:

> Ahem A Rivet's Shot <steveo@eircom.net> wrote in
> news:20220412215041.4d886828b60f91efd0c50d74@eircom.net:
>
> > [1] There was a close call with sucking air into the gas pipes but
> > that was averted by quick thinking as all the bunsen flames in the lab
> > shrank.
>
> A couple of lads in my school year got into the service ducts and swapped
> over the gas and water. Expelled. One of them became a successful pop
> star and (quick gurgle) is still touring.

Our case was much simpler - the ingenious experimenters involved
found the gas pressure was too low for their venturi based flame test
apparatus and so decided to augment it with the aid of a vacuum pump. It
jbexed fine there was enough pressure to atomise the sample into the gas
flow and the eight foot long flame was nice and easy to aim spectroscopes
at.

With all that going on noticing the bunsen flames shrink and
reacting correctly was IMHO pretty good going - no it wasn't me, I was on
the other side of the lab concocting my own abuse of the electrickery mains.
Did you know that a standard brown 13A fuse will repeatedly take at least a
thousand amps for a millisecond but it does terrible things to the mains
waveform throughout the building as we found with a flattery silly scope.

Kids today don't get to do lab jbex like that, I can't think why.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/

In article <20220412215041.4d886828b60f91efd0c50d74@eircom.net>, Ahem A
Rivet's Shot <steveo@eircom.net> on Tue, 12 Apr 2022 at 21:50:41 awoke
Nicholas from his slumbers and wrote
>On Tue, 12 Apr 2022 08:35:52 +0100
>"Brian Gaff \(Sofa\)" <briang1@blueyonder.co.uk> wrote:
>
>> I guess the ultimate ones were van der Graff generators, and windhurst
>_______________________________________________________________^^^^^^^^^
>
> Wimshurst - we had an 18 plate one at fpubby until some safety
>inspectors found it. It could charge a brass doorknob up well enough to
>give a surprise to the next person opening the door DAMHIK.
>
> They also took away the 5kV high voltage supply with the sticker
>mentioning that "Your drop dead current" was substantially less than its
>capability.
>
> Despite these (and several other) dangerous things having been in
>the fpubby forever the only nearly fatal electrical[1] accident in the
>physics labs involved the putatively safe battery box with four D cells and
>a bunch of bananananana sockets. The O level failure candidate had picked
>up one with bat flatteries innit and decided that the cure was to connect
>the outer sockets to the live and neutral of the mains socket at the back
>of the bench with leads and bananananana plugs (I presume he used a spare
>one to open the shutters). He straightened up from switching the power on
>just in time to avoid the flatteries going through him on their way to
>making a mess on the ceiling. We were in the lab next period and got the
>story fresh from a somewhat shaken teacher.

A failed candidate for 'O' level and for a Darwin Award for a
contribution to human evolution, by being still alive.
>
>[1] There was a close call with sucking air into the gas pipes but that was
>averted by quick thinking as all the bunsen flames in the lab shrank.
>
Fortunately no innocent parties were injured, but it must have been a
close call.

--
0sterc@tcher -

"Où sont les neiges d'antan?"

Ahem A Rivet's Shot <steveo@eircom.net> wrote in
news:20220413113048.9cd55b04f366c84aea15051a@eircom.net:

>
> Kids today don't get to do lab jbex like that, I can't think why.
>

Same with chemistry. I was allowed access to all sorts of stuff that
nowadays are banned for adults, let alone kids. Shame really. Knowing that
the chemicals you're playing with could put you in horse spittal does help
concentrate the mind.

--
Peter
-----

In article <20220413113048.9cd55b04f366c84aea15051a@eircom.net>, Ahem A
Rivet's Shot <steveo@eircom.net> on Wed, 13 Apr 2022 at 11:30:48 awoke
Nicholas from his slumbers and wrote
>
> Our case was much simpler - the ingenious experimenters involved
>found the gas pressure was too low for their venturi based flame test
>apparatus and so decided to augment it with the aid of a vacuum pump. It
>jbexed fine there was enough pressure to atomise the sample into the gas
>flow and the eight foot long flame was nice and easy to aim spectroscopes
>at.
>
> With all that going on noticing the bunsen flames shrink and
>reacting correctly was IMHO pretty good going - no it wasn't me, I was on
>the other side of the lab concocting my own abuse of the electrickery mains.
>Did you know that a standard brown 13A fuse will repeatedly take at least a
>thousand amps for a millisecond but it does terrible things to the mains
>waveform throughout the building as we found with a flattery silly scope.
>
> Kids today don't get to do lab jbex like that, I can't think why.
>
Question is should teachers do yno work?

We had one teacher cut of a piece of white phosphorous off and leave the
large remaining piece of white phosphorous out on the demonstration
bench. He only remember when the inevitable happened. There was a dirt
big charred depression left on the bench. I am glad to say that I was
not in his class.

Another teacher told us about the demise of one of his teachers, who put
a bottle of sodium, stored under oil, under the water tap. He told us
that while holding such a bottle in his hand, looked up to see no one
visible above their respective benches. He said "I am glad to see that
you have all been listening to my lessons".
--
0sterc@tcher -

"Où sont les neiges d'antan?"

Peter said:
> Ahem A Rivet's Shot <steveo@eircom.net> wrote in
> news:20220413113048.9cd55b04f366c84aea15051a@eircom.net:
>
>>
>> Kids today don't get to do lab jbex like that, I can't think why.
>>
>
> Same with chemistry. I was allowed access to all sorts of stuff that
> nowadays are banned for adults, let alone kids. Shame really. Knowing that
> the chemicals you're playing with could put you in horse spittal does help
> concentrate the mind.

Our A-level notes told us that if we sniffed something that smelt of
bitter almonds, it was cyanide and we should be doing it in The Gas
Cupboard.

OTOH, they never did give us any cyanide to sniff.

--
Richard Robinson
"The whole plan hinged upon the natural curiosity of potatoes" - S. Lem

My email address is at http://qualmograph.org.uk/contact.html

On 13/04/2022 15:17, Peter wrote:
> Ahem A Rivet's Shot <steveo@eircom.net> wrote in
> news:20220413113048.9cd55b04f366c84aea15051a@eircom.net:
>> Kids today don't get to do lab jbex like that, I can't think why.

> Same with chemistry. I was allowed access to all sorts of stuff that
> nowadays are banned for adults, let alone kids. Shame really. Knowing that
> the chemicals you're playing with could put you in horse spittal does help
> concentrate the mind.

Same with metaljbex, for me - although it couldn't have been called lab
jbex, it was still something that would never have been allowed these days.

I was allowed to molish (out of very thick sheet aluminium) the chassis
of a 250-volt and 6.3-volt power supply for running the valved equipment
- mainly amateur receivers and transmitters - which I molished at home.

Once the said chassis was finished, they were perfectly happy to let me
build the unit and test it. This included fitting two EY84 rectifier
valves, which had about 650 volts AC between their bare top cap clips,
and adding a series regulator circuit using a 6080 series pass valve, an
EF91 DC amplifier, and an 85A2 gas-discharge voltage reference tube.

I had recovered the mains transformer from an old AC-only WWP of the
very early '50s. The transformer had an EHT winding of a few kV, in its
own insulated section on the core. I hacked off that winding with a
hammer and chisel, and replaced it with enough turns to give me an extra
6.3-volt winding at a few amps, for valve heaters.

It all jbexed first-go, and the metalwork master was not at all worried
about my safety during the building and testing. I used the unit for
several years, and eventually sold it, IIRC at a radio rally.

--
Regards,
Andrew.

On 09/04/2022 10:34, Thomas Prufer wrote:
> On Sat, 9 Apr 2022 09:25:04 +0100, "Brian Gaff \(Sofa\)"
> <briang1@blueyonder.co.uk> wrote:
>
>> The early ones did wear out though, but they gave free replacements. I need
>> one for myself on this sofa. I get up andgo to the other side of the room
>> and get a huge spark from the part of me which touches a large metal object,
>> especially if its earthed as well.
>
> Dilute solution of fabric softener.
>
> For the sofa and carpet, not for records...

Will it work on the cat?

On 13/04/2022 15:30, Richard Robinson wrote:
> Peter said:
>> Ahem A Rivet's Shot <steveo@eircom.net> wrote in
>> news:20220413113048.9cd55b04f366c84aea15051a@eircom.net:
>>
>>>
>>> Kids today don't get to do lab jbex like that, I can't think why.
>>>
>>
>> Same with chemistry. I was allowed access to all sorts of stuff that
>> nowadays are banned for adults, let alone kids. Shame really. Knowing that
>> the chemicals you're playing with could put you in horse spittal does help
>> concentrate the mind.
>
> Our A-level notes told us that if we sniffed something that smelt of
> bitter almonds, it was cyanide and we should be doing it in The Gas
> Cupboard.
>
> OTOH, they never did give us any cyanide to sniff.
>
>

The real problem occurs for those unfortunates that can't smell cyanide.
It's genetic IIRC.

--
Chris Elvidge
England

On 13/04/2022 15:25, Nicholas D. Richards wrote:
> In article <20220413113048.9cd55b04f366c84aea15051a@eircom.net>, Ahem A
> Rivet's Shot <steveo@eircom.net> on Wed, 13 Apr 2022 at 11:30:48 awoke
> Nicholas from his slumbers and wrote
>>
>> Our case was much simpler - the ingenious experimenters involved
>> found the gas pressure was too low for their venturi based flame test
>> apparatus and so decided to augment it with the aid of a vacuum pump. It
>> jbexed fine there was enough pressure to atomise the sample into the gas
>> flow and the eight foot long flame was nice and easy to aim spectroscopes
>> at.
>>
>> With all that going on noticing the bunsen flames shrink and
>> reacting correctly was IMHO pretty good going - no it wasn't me, I was on
>> the other side of the lab concocting my own abuse of the electrickery mains.
>> Did you know that a standard brown 13A fuse will repeatedly take at least a
>> thousand amps for a millisecond but it does terrible things to the mains
>> waveform throughout the building as we found with a flattery silly scope.
>>
>> Kids today don't get to do lab jbex like that, I can't think why.
>>
> Question is should teachers do yno work?
>
> We had one teacher cut of a piece of white phosphorous off and leave the
> large remaining piece of white phosphorous out on the demonstration
> bench. He only remember when the inevitable happened. There was a dirt
> big charred depression left on the bench. I am glad to say that I was
> not in his class.
>
> Another teacher told us about the demise of one of his teachers, who put
> a bottle of sodium, stored under oil, under the water tap. He told us
> that while holding such a bottle in his hand, looked up to see no one
> visible above their respective benches. He said "I am glad to see that
> you have all been listening to my lessons".
>

When I was at school, one of my classmate niched the school supply of
potassium, but then didn't know what to do with it.
He flushed it down the bog.

--
Chris Elvidge
England

On 12/04/2022 11:24, Adrian Caspersz wrote:
> On 12/04/2022 08:17, Brian Gaff (Sofa) wrote:
>
>> At one show there was something called a vinyl rescue system. Best
>> part of
>> 10,000 quid. It played the disc with lasers and could be adjusted so it
>> played part of the grooves with no or minimal wear. The Japanese made
>> it and
>> it must have been the ultimate in the law of diminishing returns!
>
> There is a video on the youtubes on that one. It didn't work
> particularly well for the expense.
>
> Perhaps, as we are now in the era of machine learning, someone could
> have another go?
>
> Don't need lasers. I'd just glue a weight compensated webcam with
> microscope lens to the headshell, using the stylus to guide it. And do a
> crazy amount of signal processing to turn the pictures into sound.

Why bother rotating the record? Just scan it at extremely high
resolution and work all the wiggly bits out from that.

On Wed, 13 Apr 2022 15:25:47 +0100
"Nicholas D. Richards" <nicholas@salmiron.com> wrote:

> Question is should teachers do yno work?

Hmmm, that's a good one.

> We had one teacher cut of a piece of white phosphorous off and leave the
<snip>

Our fifth form chemistry teacher's talk on lab safety was cut
short. He walked round in front of his bench and leaned back against it to
provide that friendly informal touch as he began to talk about the various
dangers awaiting those careless in the lab. He only got a couple of
sentences in before he was interrupted by shouts of "Sir, you're on fire!"
from those of us who were awake.

He had neglected to turn down the bunsen burner in the middle of
his desk. He did give an excellent demonstration of what to do as he
removed his jacket and extinguished the flames but he did not see fit to
continue his talk on lab safety afterwards.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/

On Wed, 13 Apr 2022 09:30:03 -0500
Richard Robinson <richardR@privacy.net> wrote:

> OTOH, they never did give us any cyanide to sniff.

It was a chemistry lab, you're supposed to molish it.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/

On Wed, 13 Apr 2022 01:22:56 +0100
"Nicholas D. Richards" <nicholas@salmiron.com> wrote:

> In article <20220412215041.4d886828b60f91efd0c50d74@eircom.net>, Ahem A
> Rivet's Shot <steveo@eircom.net> on Tue, 12 Apr 2022 at 21:50:41 awoke

> >[1] There was a close call with sucking air into the gas pipes but that
> >was averted by quick thinking as all the bunsen flames in the lab shrank.
> >
> Fortunately no innocent parties were injured, but it must have been a
> close call.

We (including physics teacher) reckoned we were perhaps a minute or
two from unmolishing the lab block.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/