Phonovision not digital?

[Viewmaster]

In the case of the standard 2.1875 inch diameter cylinder rotating at 160 rpm (2.66667 rev/sec), the surface speed is 2.1875×pi×2.66667 = 18.33 inches per second (ips). With a standard 2.7 mil (.0027 inch) conical stylus, the minimum reproduceable wavelength would be .0054 inch. Therefore, the maximum reproduceable frequency would be 18.33/.0054 = 3394 Hz. With a special elliptical stylus that would have a minimum dimension of 1.2 mil, the maximum reproduceable frequency would be 18.33/.0024 = 7638 Hz.


This indicates that even with a special elliptical stylus, the standard cylinder rotating at 160 rpm could not adequately reproduce our standard NBTV signals. We would need to use the larger "Concert" cylinders or a higher cylinder speed. .

Thanks for all those calculations Stephen.
But we have always known, haven't we, that a standard cylinder would only produce a degraded NBTV image? I certainly did mention this some time ago that I was prepared to accept this.

I suppose it's all a case of what one is trying to achieve. Either a good reproducing system......use a CD for first choice or discs as you indicated, or an historic project just to see how cylinders and NBTV combined might look. Edison was going along this track but abandoned the idea as film came in.
Concert cylinder blanks are £37 each by the way.
If I ever built a combined NBTV/cylinder machine I would call it a "Edikow"
in memory of Edison and Nipkow...my proposed seperate cylinder machine just an"Edi"
Anyway, the solving of the cyl sync problem is an interesting challenge even if it eventually just leads to a crappy looking image

Albert.

[Viewmaster]

All you do is change the Nipkow disc for a different recording.

Now who's going to have a go at a jukebox? (Please, no coin-slot).

Steve A.

Make it a horizontal Nipkow auto changer....load up 8 Nipkow
discs which drop one at a time onto a turntable.
....or how about 8 cylinders in a long line which shuffle along to be played one at a time
Albert.

[Stephen]

I liked the idea of a Phonograph system and I still do. But does it make any sence if we don't want to use a 320 rpm system with half a minute recordings?

There is another possibility that I only mention with caution--microgroove. With microgroove recording and an elliptical playback stylus with 0.7 by 0.3 mil dimensions, the frequency response limit will extend upward by a factor of four. Playing time will increase by a factor of four as well.

The primary problem with microgroove is groove wear on a wax or laquer surface. Stylus pressure on the groove walls increases dramatically because of the reduced "footprint" of the stylus on the groove. This means one has to have a reproducer with very good compliance and low moving mass. Also, any imperfections or dust on the recording surface can have a disasterous effect on the quality of the recording.

Nevertheless, there is precedence for microgroove recording in the 1920s. Thomas Edison produced microgroove Diamond Disc recordings in 1926 that had a playing time of 40 minutes.

[DrZarkov]

I know those diamond discs, a friend of mine has some of those records and an Edison disc phobograph. The quality is excellent, by far the best acoustic sound of that time. (Once many years ago I've made an experiment with a 45 rpm single (of course with a disgusting "Schlager" on it) on my grammohone, the motor slowed down to the minimum which was about 45 rpm. The quality was better than any schellac, and even better than many cheap record players. Of course you could use the record only once, you really saw the difference...).

So why not micro-grooves? Wax is no good idea then, but how about using Fimo, which I've suggested before? It's a kind of PVC with a softener in it, which disappears after heating, letting back PVC? Even making of your own blank cylinders is a question of minutes! Of course there was no PVC in the 30th, but there was blue amberol, which we do not have any more.

[Stephen]

I know those diamond discs, a friend of mine has some of those records and an Edison disc phobograph. The quality is excellent, by far the best acoustic sound of that time. (Once many years ago I've made an experiment with a 45 rpm single (of course with a disgusting "Schlager" on it) on my grammohone, the motor slowed down to the minimum which was about 45 rpm. The quality was better than any schellac, and even better than many cheap record players. Of course you could use the record only once, you really saw the difference...).

So why not micro-grooves? Wax is no good idea then, but how about using Fimo, which I've suggested before? It's a kind of PVC with a softener in it, which disappears after heating, letting back PVC? Even making of your own blank cylinders is a question of minutes! Of course there was no PVC in the 30th, but there was blue amberol, which we do not have any more.

I agree, the Diamond Discs are better than any other acoustic records by far.

I agree with you that Fimo may be a good way to make permanent durable recordings on disc or cylinder. I understand that it has been available since the 1930s, but I was never aware of it. I wonder if it is suitable for cutting by a conventional cutting stylus. If it is, this material may be ideal. If not, it might be possible to emboss it instead. That would be more complicated though for lack of easily procuring a microgroove embossing stylus.

[DrZarkov]

You can work with Fimo like with knead or wax: As long as you form it, it is very soft. After waiting some time it will be relative hard, hard enough that you can cut it. It's really worth a try.

[Viewmaster]

Could I add a note of caution....
One of the problems with micro groove (and 78!) was the rumble from
turntables. Unless one could afford a high quality one such as the Garrard
301 then rumble was a problem. With a cyl machine this will probably
manifest itself in gear rumble as well as rotational rumble. Although not
too noticable on medium Hi Fi sound it will be very noticable on NBTV manifesting itself as moving areas of modulation... nasty!

Also with hill and dale there are no problems with any lateral movement of the cylinder or carriage leadscrew. But with lateral recording, all these
will be possible causes of trouble.
With micro groove we are dealing with lateral recording movements in the
.0001inch area or less for high freq/low output signals. So any machine movements will impose themselves on the signal.

Rumble, which can be filtered out to some extent with sound only recordings cannot with pictures.

So I think that hill/dale would be less susceptable to some of these
problems. But who can be sure?

I fear that the problems are in more areas than we may have first thought!

Sorry to be so negative. but these are real problems any maker
of a Edikow machine will have to face in designing and building it.
Albert.

[Steve Anderson]

Could I add a note of caution....
One of the problems with micro groove (and 78!) was the rumble from
turntables.Albert.

Although not directly related I remember an incident regarding rumble and the like. In the very early 80s I was working at a radio station in the west-country of England. Once a year the IBA (Independent Broadcast Authority) would decend upon us and check that all things technical were up to scratch. (excuse the pun).

They would bring with them test tapes, discs and cartridges and a whole pile of test gear to check the standards were being adhered to. We had just installed Technics SL1200 direct-drive turntables at that point, some of the first in the country.

The figures they got when testing them they couldn't believe, thinking their test-gear was faulty they went away and came back a week later with recalibrated test equipment and new virgin test discs. The figures came out almost the same.

These turntables were so good (and still are, you can still buy them), that what they were measuring was the latent wow, flutter, rumble ond so on from the machine that actually cut the master!

They went away with their tail between their legs.

Steve A.

The other thing I might mention was that I installed Ortofon moving coil cartriges with battery-powered pre-amps. These were so flat that the IBA also raised their eyebrows! Hum? What hum?

[DrZarkov]

I'm still very happy with my Technics SL 1200 which I've got 18 years ago on a dutch flea-market for 55 Hfl (about 17 Pound).

I saw that there is a disc-cutting kit available for my record-player for about 2000 EUR. This would surely be a good recording device for NBTV.

[Steve Anderson]

I'm still very happy with my Technics SL 1200 which I've got 18 years ago on a dutch flea-market for 55 Hfl (about 17 Pound).

You were lucky! In profession circles they change hands for a lot more than that! Keep a hold of it!!

Steve A.

[Stephen]

You can work with Fimo like with knead or wax: As long as you form it, it is very soft. After waiting some time it will be relative hard, hard enough that you can cut it. It's really worth a try.

The other interesting thing is that all the available cutting stylii have integral heating coils. With such a coil energised during recording, the heated stylus may harden the groove as it cuts it.

Now does anyone have a pottery wheel to make Fimo cylinders?

[DrZarkov]

I don't think it will harden it unless it will not become warmer than 110 degrees (Celsius). A little bit warmer (say 40 degrees) will it even make softer.

[Stephen]

There is another American company by the name of Transco in New Jersey that makes lacquer recording blanks that are somewhat less costly than those from Apollo. See http://www.transcousa.com/lds.html . By the way, "dubs" are perfectly fine for making recordings. As I understand it, they simply do not have the degree of mirror surface needed for producing commercial matrices.

[Stephen]

I just discovered a forum for disc/cylinder recording. It is the "Secret Society of Lathe Trolls" at http://lathetrolls.phpbbweb.com/lathetrolls.html .

[Steve Anderson]

The "Secret Society of Lathe Trolls."

Even with my somewhat distorted perspective on life, is this getting a little out of hand? I mean, "Lathe Trolls."? I have to admit though it looks good!

Steve A.