Mechanical video recorder

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Re: Mechanical video recorder

Postby Klaas Robers » Sat Jul 27, 2019 6:36 am

Harry, something comes in my mind again. In the 78 rpm-time the cutting needle was used only once, for one disc side. It weared off so much and so fast, that after one disc side it was replaced and discarded. That was the reason that when recording a grammophone record, the disc was recorded from the inner side and spiraling towards the outher side. At the inner side the groove on the disc runs slowest, so the cutting stylus should have the most optimal shape. During the recording process, the stylus weared off and the groove became more and more misformed. But there the groove speed became higher, so the misformation was causing less distortion.

So when recording, record from the inner side, spiraling towards the rim of the disc. I have two of those discs, recorded discs. They were recorded in february 1945 here in Eindhoven, at Philips.

And yes, pressed and bought discs should be played starting at the rim and spiraling in, but that had a totally different reason.
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Re: Mechanical video recorder

Postby Harry Dalek » Sat Jul 27, 2019 5:32 pm

Klaas Robers wrote:Harry, something comes in my mind again. In the 78 rpm-time the cutting needle was used only once, for one disc side. It weared off so much and so fast, that after one disc side it was replaced and discarded.


The tiny size of the cutting head i would believe that for sure ! i wonder what they used at the start just steel ?,i have not heard of that type of wear these days ..i will look into it but i would be very costly some cutting stylus are 80 dollars for one .. some are selling old cartridge's with cutter at crazy prices .
The metal ones you can get one with shipping for 30 dollars.

That was the reason that when recording a grammophone record, the disc was recorded from the inner side and spiraling towards the outher side. At the inner side the groove on the disc runs slowest, so the cutting stylus should have the most optimal shape. During the recording process, the stylus weared off and the groove became more and more misformed. But there the groove speed became higher, so the misformation was causing less distortion.


That's some thing again i have never come across ...there was some science going into developing the record and formats ever come across a 16 RPM ? have that one old 50s player ....
Now i have to do my try's with junk laying around bit of repurposing .... the cutting or scratching the audio will be done on the cheap ..

So when recording, record from the inner side, spiraling towards the rim of the disc. I have two of those discs, recorded discs. They were recorded in february 1945 here in Eindhoven, at Philips.
And yes, pressed and bought discs should be played starting at the rim and spiraling in, but that had a totally different reason.


How long if the format last Klaas ? or was it just experimental ?
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Mechanical video recorder

Postby Harry Dalek » Sat Jul 27, 2019 5:32 pm

Klaas Robers wrote:Harry, something comes in my mind again. In the 78 rpm-time the cutting needle was used only once, for one disc side. It weared off so much and so fast, that after one disc side it was replaced and discarded.


The tiny size of the cutting head i would believe that for sure ! i wonder what they used at the start just steel ?,i have not heard of that type of wear these days ..i will look into it but i would be very costly some cutting stylus are 80 dollars for one .. some are selling old cartridge's with cutter at crazy prices .
The metal ones you can get one with shipping for 30 dollars.

That was the reason that when recording a grammophone record, the disc was recorded from the inner side and spiraling towards the outher side. At the inner side the groove on the disc runs slowest, so the cutting stylus should have the most optimal shape. During the recording process, the stylus weared off and the groove became more and more misformed. But there the groove speed became higher, so the misformation was causing less distortion.


That's some thing again i have never come across ...there was some science going into developing the record and formats ever come across a 16 RPM ? have that one old 50s player ....
Now i have to do my try's with junk laying around bit of repurposing .... the cutting or scratching the audio will be done on the cheap ..

So when recording, record from the inner side, spiraling towards the rim of the disc. I have two of those discs, recorded discs. They were recorded in february 1945 here in Eindhoven, at Philips.
And yes, pressed and bought discs should be played starting at the rim and spiraling in, but that had a totally different reason.
[/quote]

How long if the format last Klaas ? or was it just experimental ?
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Mechanical video recorder

Postby smeezekitty » Sat Jul 27, 2019 5:40 pm

Harry Dalek wrote:That's some thing again i have never come across ...there was some science going into developing the record and formats ever come across a 16 RPM ? have that one old 50s player ....
Now i have to do my try's with junk laying around bit of repurposing .... the cutting or scratching the audio will be done on the cheap ..

There are even 8 RPM records... https://www.youtube.com/watch?v=13bTMRtGOaA
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Re: Mechanical video recorder

Postby Harry Dalek » Sat Jul 27, 2019 6:08 pm

To day i gave my Stylus scratching debossing ? idea ago a very primitive go indeed just to see if it had promise and it does record and play back...i just did this with holding the thing together with a little tape and hand tracking all not the most precise way of doing things here but it was just an experiment its so badly knocked up its amazing it worked at all a few seconds of holding the cartridge and trying to track it

Just using a little transistor radio to feed the speaker stylus.

I reused the tiny laptop speaker with pen cone and needle but the needle is just to transfer the vibrations to the old player cartridge stylus i had pulled apart since it didn't seem to work as it was any more .

Its small enough to try on the project which is good least its a little step forward .Track and stylus match might wear it out but what the hell its cheaper than a cutting stylus .


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MVI_0105_x264.mp4
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the stylus i used here very old !
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Here's a dual head one i have one looks to have flat sides
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Mechanical video recorder

Postby Harry Dalek » Sun Jul 28, 2019 7:13 pm

I tried another record today but this time with the little lathe to cut or scratch in the tracks ,this works well but also tried modulation and it does record not overly well yet the PC sound card for a start is a touch low and i forgot about the angle of cut i think about 60 degrees i am dead vertical here Whoops !
Tried with a NBTV test card for the record just for the hell of it
Problems like my globe went which i needed for the strobe disk so just a guess it here for correct speed of record i was trying for 45 RPM here for record and play back but on the other player i can hear i was off a touch trying to cut down noise running slower .
I am starting to understand what will work , i don't think i would have the bandwidth yet for NBTV a stable record still aways off so i may start experimenting with recording 8 Sec SSTV .
When things get better i would like to see what happens to recorded 400hz sync pulses....and do a frequency sweep .
A little step forward today bit more tweaking see what happens next week.




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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Mechanical video recorder

Postby Harry Dalek » Tue Jul 30, 2019 11:54 pm

Hi Albert if your out there reading some past post finding more as I go but I think the thread I was reading you were saying you got at that time 3.8khz record band width using 78 rpm were you able to improve on this ...
once I can I really need to do a freq sweep test .
My turntable will do over 78 rpm but I need to dampen the gear noise ...so my original thinking is go standard only reason have a known working player..... till I know I can do the same on my turntable wise to stick with something that works .
I like how you stuck to your guns and knew you just wanted to see how the idea would work out and did so .
On the record side of things there were home recordings on record from the 30's but video only https://www.tvdawn.com/earliest-tv/the- ... ding-1933/
What gets me this is a home recording of not even closeups and looks be better than phono vision due to the size of the subjects...a 30's hobbyist.
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Re: Mechanical video recorder

Postby Viewmaster » Wed Jul 31, 2019 8:08 pm

Harry, it was 10 years ago so I cannot remember small detail.
But the upper freq response was never good. Bear in mind that I was
cutting wax Dictaphone cylinders. It is a very soft medium to work
with compared with the very hard CD surface you are working on.

So you are in a different ball game entirely, my freq response will
not bare compaarison with your CD's.
If you do sweep tests and look at results under a microscope
it is easy to work out your response knowing the inches per second of
your cutting speed.

As I cut on a cylinder I didn't have the speed variation that disc cutting has.

I hope that eventualy you are a cut above me! :lol:
“One small step for a man,"......because he has Arthritis.
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Re: Mechanical video recorder

Postby Harry Dalek » Wed Jul 31, 2019 8:57 pm

Viewmaster wrote:Harry, it was 10 years ago so I cannot remember small detail.
But the upper freq response was never good. Bear in mind that I was
cutting wax Dictaphone cylinders. It is a very soft medium to work
with compared with the very hard CD surface you are working on.


I was going to ask when they say wax do they mean wax ? or softer plastic i have never looked into it .
No problems Albert i read a bit each night on your work and forget it was a while back for every one ....i picked up on the bandwidth as it might of been low but you manged some thing that worked

So you are in a different ball game entirely, my freq response will
not bare compaarison with your CD's.


Oh i see.... i might be more lucky a record does have the bandwidth but as far as my home construction we will see ..record play back and syncing the 3 Amigos !

If you do sweep tests and look at results under a microscope
it is easy to work out your response knowing the inches per second of
your cutting speed.


I will look for sure ....my microscope is about as good as the stylus images i will give it a look for sure see if it will make a track or 2 viewable.

As I cut on a cylinder I didn't have the speed variation that disc cutting has.


I can adjust my Turn table speed ,it pops up on some videos i have watched on those that record the lathe slows down the speed on record they don't have a way to correct this on play back ,i can do a manual speed adjustment the the geared motor but it would be good if turntable speed could correct this on either i just want to see for a start what it can do as is .

I hope that eventualy you are a cut above me! :lol:


Matching would be nice Albert .... :wink:
i would be really happy with some thing in sync ,easy start would be SSTV its nice and low in bandwidth see how that gos then NBTV .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Mechanical video recorder

Postby Harry Dalek » Fri Aug 02, 2019 5:51 pm

I can record and play back now on the same machine now not overly great still but i can do it now ,need to work on the depth of cut angle and such the knock up today i can now do this easier ...Quality of recording needs work but as is it should record and play back at at a range of RPM
The Play back is a quick magnetic change to the non magnetic Stylus cartridge but i have one coming, i needed some thing to test my recordings .

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IMG_0133.JPG


The New lathe change i made it so i could adjust depth of the track cut ,i will do some videos next time .
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Mechanical video recorder

Postby Viewmaster » Fri Aug 02, 2019 8:28 pm

You're lucky, Harry, in that on playback you have a hard surface to track over.
I had just hard wax to contend with so I had to use the lightest of pick ups
to prevent groove wear.
Your rig is looking good. What's the sync situation like now?
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Re: Mechanical video recorder

Postby Harry Dalek » Fri Aug 02, 2019 11:59 pm

Viewmaster wrote:You're lucky, Harry, in that on playback you have a hard surface to track over.
I had just hard wax to contend with so I had to use the lightest of pick ups
to prevent groove wear.
Your rig is looking good. What's the sync situation like now?


Hi Albert Yes sounds hard to have worked with a waxy surface you had to deal with !
Why did they use that is it easy to cut a layer off and reuse it ?
I always try to be careful with recording as i can only do it once and need to find another cd or dvd for the next test ...Horder i keep the mistakes for future Nipkows !
I had to change the lathe part to a better idea as needed to control that depth of cut at times it changes the record speed if i cut to deep this change should work better as i can now control that .
Well sync as to i record play back it is the same what ever RPM i leave it at so long as the cut again isn't to deep ..well i haven't tried to many ranges as if i have the turn table running to fast the tracks will be very close ,i will have to see what the limits are here and the cutting arm speed.
I have ordered a store magnetic stylus cartridge and a cutting stylus i can bolt on to this later when they turn but for now i will see how well i can do this on the cheap with junk .
As far as Correct syncing for some thing critical such as video of some sort where speed has to be spot on such as SSTV.
I will see if a SSTV recording records well at all or for play back and expect it to go out of sync ...hope at least slowly ...SSTV should be easiest video to try if it can't do that it will have no hope at NBTV levels have to be at correct ,i don't have a preamp just direct to lap top mic input at the moment but its ok for voice music .
On the player side of it tried it with a 78 record lifted off the turnable with a little can just to see how well my knock up stylus to magentic stylus played a normal record it was pretty good , with my cd record levels are lower but .
I seem to be building out of its case i want it to work than make it fit at the moment ...i am pleased i have some sort of mechanical recorder player do learn a lot playing with this ...Again i wack some videos up when i have time this week end ..have to fix my hedger tomorrow morning boring work :roll:
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Re: Mechanical video recorder

Postby Harry Dalek » Sun Aug 04, 2019 6:50 pm

Bit more work up an down as i have been changing things to do with the stylus so the record side still needs heaps of work ! i wasn't really happy with recordings on pc from the player side its ok to listen to and know how something recorded but took for the first time i took the recording cds to the store player and see how well they went on it .
Below is a 8 sec sstv try on what i think is close to 45 rpm and was not expecting to do this so its a bit off speed for sure ..i tried seeing if it played back mainly from direct play to one of the sstv programs but best i noticed was sync was off changing player speed didn't really help .



Think i tried some scottie1 sstv here


Below some audio try's kept is short still sounds a touch muffled shocking it was again pretty close to 45rpm on my turn table to play on this one





Many mistakes all the tries the fails so far on my (Dusty guttered gramophone some one in the 50s turned it into a 50s electric turntable and for good measure Drilled sound holes around the turntable ...but....then never used them for a speaker just went with connections for amp they must of had ) Yes i will give it a dust least it still has the original turn table just every thing else is gone !)

IMG_0157.JPG


The ones that worked so far !

IMG_0159.JPG


I tried instead of just touching here soldering the stylus to the arm i did learn working with it the stylus i am using it to scratch the sound on the cd's it has to be vertical unlike the needles other wise it doesn't cut the tracks .
I do have a lathe stylus coming so i will just experiment till then .

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Attachments
MVI_0148_x264.mp4
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MVI_0149_x264.mp4
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MVI_0150_x264.mp4
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MVI_0152_x264.mp4
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Last edited by Harry Dalek on Mon Aug 05, 2019 10:07 pm, edited 2 times in total.
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: Mechanical video recorder

Postby smeezekitty » Mon Aug 05, 2019 10:03 am

Harry Dalek wrote:i noticed was sync was off changing player speed didn't really help .

Most likely because there is quite a bit of frequency (speed) instability
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Re: Mechanical video recorder

Postby Harry Dalek » Mon Aug 05, 2019 5:46 pm

smeezekitty wrote:Most likely because there is quite a bit of frequency (speed) instability


Yep the turntable it will have to be synced for any thing to do with video and wouldn't hurt for any normal Audio as well ..thinking of going down the 50hz road syncing the thing with a strobe disc and 50hz crystal clock replacing the strobe disks for 33 45 78 rpm it would change speed to the correct rpm depending on the one used opto switch PLL some motor speed control ...if that's good enough ?
I think this would be less of a headache than trying to sync the disk via sync pulses ...going down that road is complex if possible at all at these low rpm record speeds
Playing around of late it seems to work best on 45 rpm...as far as cutting tracks and recording .
But before all this i still need to rethink the lathe cutting side this was a nice first try cutting head but reading and learning some more i think i can improve onit and need to experiment more ..
These pickups are very similar to the first cutting heads .
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Love the this 30s recorder ...has some bits Albert mentioned on counter weights due to the record head being to heavy ..the guide needle using another record for tracking the recording is a wonderful idea none one uses now so simple
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Attachments
BBC Recording Training Manual.pdf
rather good book on sound recording
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Practical_Disc_Recording_(1948)_Richard_H_Dorf.pdf
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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