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EVR Electronic Video Recording

 
Sundog
(@sundog)
Busy V-Ratter Registered

Before any home tape formats, a system called EVR existed. Developed by CBS, players were made by CBS and a number of other Japanese companies including Mitsubishi who had a model of which I worked on a few.

The system concept is quite simple. The medium is 8.75mm monochrome film with a central division. For colour playback half the film is a luminance image while the other half has a subcarrier graticule. Sound is magnetic.

The player consists of a flying spot tube and beam splitter that is optically coupled to 2 photo-electric cells.

The Y cell supplies a conventional video amplifier. The C cell output is amplified and by filtering is split into a signal path and a pilot path.These are then Processed and converted to either 3.58MHz NTSC or 4.43MHz PAL. There were different models for PAL and NTSC and there were different films.

There was some particular cleverness in the conversion process to allow an NTSC or PAL output even though the film had straight quadrature modulation. This was easily demonstrated by the scan horizontal linearity setup was done on a single colour frame and set for evenness of hue.

The loading mechanism deserves some explanation. When a reel is placed in the machine and the play button is pressed, the reel is stretched apart slightly, allowing the leader barb to spring out an get picked up by the loading mechanism.

Manufacturing the film required greater accuracy that can be done in a conventional film lab. A special process was developed using electron beam scanning, which of course had to be done in a vacuum. Films for the UK were made in the basement of 142 Wardour St.W1. Ironically I went on to spend several years working in that basement which was then a TV facilities company.

Here is a link to a good article with some pictures:

https://www.terramedia.co.uk/media/video/evr.htm

It was never successful as a home format. Most of the Mitsubishi EVRs spent their time playing out information films at airports and the like. You could set one on auto-repeat and leave it playing for months or years with hardly any deterioration in media, unlike videotape.

I have read that the system was capable of carrying 2 sets of monochrome images. I never saw a film like this and don't think our machine would have coped.

 

 

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Topic starter Posted : 25/11/2021 7:00 pm
helloekco and Alex728 liked
Jayceebee
(@jayceebee)
Noble V-Ratter Registered

@sundog Rank Bush Murphy did some work on the system in the UK and produced a very small number of machines, around twenty I'm led to believe. A collector has one and it can be seen in this thread. https://www.vintage-radio.net/forum/showpost.php?p=373096&postcount=42

 

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Posted : 25/11/2021 8:14 pm
Sundog
(@sundog)
Busy V-Ratter Registered

Yes you are right, I forgot Rank made one. In fact Rank were the occupiers of 142 Wardour St. during the EVR film production and part of my days there.

What I failed to mention is that I gave away a Mitsubishi EVR while I was working there, that had been in my loft for years. An engineer's father was a collector of "junk" (as I am now) so I happily gave it away. Sad;(

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Topic starter Posted : 25/11/2021 9:30 pm
WayneD
(@wayned)
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Is this it?

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Posted : 27/11/2021 6:08 pm
Sundog
(@sundog)
Busy V-Ratter Registered

@wayned Yes it is but the association with an LP is barmy!

I think I spy an RBM white TV for playback.

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Topic starter Posted : 28/11/2021 9:47 pm
WayneD
(@wayned)
Busy V-Ratter Registered

@sundog Yes, it looks like it although I thought these ones with the grey bezel were black and white? Colour versions not making an appearance until the mid 70s.

A black and white one that looks identical was smashed up in the first episode of the BBC drama The Changes:

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Posted : 28/11/2021 10:07 pm
Sundog
(@sundog)
Busy V-Ratter Registered

Funnily enough I remember repairing on from the BBC with lots of circuitry added that may have been for gen-lock. After removing the mods, it worked fine and was returned to them.

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Topic starter Posted : 29/11/2021 9:14 am
Cathovisor
(@cathovisor)
Illustrious V-Ratter Registered
Posted by: @wayned

Colour versions not making an appearance until the mid 70s.

If you go to the excellent website at http://www.murphy-radio.co.uk/murphybilia/murphy_bilia6.html you'll find that the "Quite White" colour Murphy dates from 1969, no less - a natural continuation from the black and white "Painted Murphys" from a couple of years prior.

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Posted : 29/11/2021 4:54 pm
WayneD liked
Sundog
(@sundog)
Busy V-Ratter Registered

@cathovisor I'd better not let my wife see those, she'll be painting our Samsung.

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Topic starter Posted : 29/11/2021 5:25 pm
WayneD liked
WayneD
(@wayned)
Busy V-Ratter Registered
Posted by: @cathovisor
Posted by: @wayned

Colour versions not making an appearance until the mid 70s.

If you go to the excellent website at http://www.murphy-radio.co.uk/murphybilia/murphy_bilia6.html you'll find that the "Quite White" colour Murphy dates from 1969, no less - a natural continuation from the black and white "Painted Murphys" from a couple of years prior.

I stand corrected! 😮 

I was always led to believe that those RBMs didn't have a colour version until the mid 70s.

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Posted : 29/11/2021 6:26 pm
Cathovisor
(@cathovisor)
Illustrious V-Ratter Registered
Posted by: @sundog

@cathovisor I'd better not let my wife see those, she'll be painting our Samsung.

They look very nice "in the wood" - I've never seen a Revolution Red one, but I have seen Dramatic Black, Quite White, Smooth Blue, Serene Green and Outrageous Orange (and it really is!) examples in my time.

 

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Posted : 29/11/2021 6:43 pm