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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 20th Dec 2011, 11:34 am   #1
brenellic2000
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Default Cine film synch - 5ips Motek

Standard tape speeds (7-1/2ips, 3-3/4ips) don't directly correspond with cine film speeds (18 frames/sec for silent, 24 fps for sound-track stock).

Clearly, depending on frame size (8mm is 80 frames per foot = 6.6 frames/inch; Super 8 is 72 frames/ft = 6 frames/inch), simple maths (in theory) tells us that at 24fps (sound) the direct tape speed should be 3.6ips for 8mm and 4ips for Super 8; or at 18ips (silent) 2.72ips or 3ips.

Motek used phase shift/change to get a 'slow' 5ips from their 'fast' 7-1/2ips using a standard Collaro motor (some sources say 4-1/2ips) to better help cine users who tended to use 3-3/4ips (the closest to cine speed - unless they had a Cinecorder with proper synchronisation).

So, how helpful was Motek's 5ips (or indeed 3-3/4 ips) to cine film users? Is it possible to get an exact speed by phase change and, if so, why would Motek chose 5ips rather than 4ips...

... or have I been at the Christmas cider a tad too early and missed something?

Barry
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Old 20th Dec 2011, 10:39 pm   #2
TIMTAPE
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Default Re: Cine film synch - 5ips Motek

Hi Barry,

Not sure what you mean by phase change here. Can you explain a bit more?

I used to have a litle Eumig P8 projector with the tape synchroniser option on the back. I think it was designed to run the film at 16fps when the 1/4" tape ran at 3.75ips. Apart from being very awkward to set up it seemed to basically stay in lip synch for a 3 minute reel of cine film. I used it with a Philips EL 3541 as I recall.

Cheers Tim
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Old 21st Dec 2011, 11:22 am   #3
brenellic2000
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Default Re: Cine film synch - 5ips Motek

Hi Tim,

I'll swap some of your warm Christmas sun for our cold, wet, damp weather!

Motek decks ran at 7-1/2ips, but instead of using idlers/stepped pulleys their early decks used a phase shift/change to get a lower, 2nd speed 'to help cine film users' - ie: 5ips (although some sources say 4-1/2ips).

As I say, I've never use cine cameras so am mystified why the speed of the tape recorder was necessary to match a cine-camera, unless the magnetic stripe cine film was passed through tape deck - yet whose tape guides were only 6mm wide. But, 16mm, 8mm and Super all differ in size of frames and number of frames per second. Can you explain this conundrum?

Merry Christmas!
Barry
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Old 21st Dec 2011, 1:10 pm   #4
TIMTAPE
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Default Re: Cine film synch - 5ips Motek

Hi Barry,

I still dont get how the Motek deck worked with a cine projector. Do you have a picture?

Sorry, no deal, Barry. I'll keep my Australian weather.

Merry Xmas to you and yours, Barry, and all on the Vintage forum.

Tim
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Old 21st Dec 2011, 2:43 pm   #5
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Default Re: Cine film synch - 5ips Motek

Barry,

16mm has 40 frames to the foot and was the 'serious' amateur gauge. (40/12)*16fps = 4.8ips so this is what Motek were probably aiming for. 18fps didn't become the standard silent speed until Super 8 came along (although B&H were secretly using it to keep their 'fire shutter' from falling at 'silent' speed).

If the tape and film speed exactly match editing is eased, because if you splice out 1 foot of film you just have to splice out 1 foot of tape.

Regards,

Paul
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Old 21st Dec 2011, 3:06 pm   #6
brenellic2000
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Default Re: Cine film synch - 5ips Motek

Ah, thanks Paul, that's answered my question admirably!

I always associated amateur cine-film buffs with 8mm stock (rather than 16mm) when using 'domestic' tape recorders - hence my dilemma over speeds.

Barry
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Old 21st Dec 2011, 5:46 pm   #7
LXSTEIN45
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Default Re: Cine film synch - 5ips Motek

I still have my grandfathers syncro-decks that use to sync a projector to his Beocord 2000 reel-reel. All designed as far as I could see to make editing life a LOT easier.
I can't remember how it was setup or how it worked and I ripped the reedswitch and plug out of the converted projector to return to its former glory. I might have a look if it would help and try to work out exactly how it worked..

BTW it loathes me to throw these syncrodecks away so if anyone wants for postage PM me.
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Old 22nd Dec 2011, 12:04 pm   #8
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Default Re: Cine film synch - 5ips Motek

Barry, I think Scophony also did a 7.2/4.8 ips version of their machine.

Lx, there are 2 types of synchrodeck. The earlier mechanical ones have the tape laced round an idler and the projector connected via a flexible shaft. A differential gearbox is used to compare the relative speeds and its output shaft is used to drive a switch which adds extra resistance into the projector motor circuit.

The later 'electronic' units have a reed switch fitted inside inside the projector to give a pulse per frame. It is used in conjunction with specially punched tape which has 18 (or 24) holes per 3.75 (or 7.5)". Tape and film can now be compared on a frame by frame basis and any difference used to alter the projector speed.

The Synchrodek was designed by a chap called Harry Garlick, and sold through his Craven instrument company. I believe he also used to own a chain of radio & TV shops.

I'm assuming it's the electronic version you have?

Regards,

Paul
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Old 22nd Dec 2011, 2:47 pm   #9
brenellic2000
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Default Re: Cine film synch - 5ips Motek

Thanks Paul,

The standard Scophony-Baird Soundmaster was single speed, 7-1/2ips; I've not heard of a 4.8ips version, but the Cine-Soundmaster which preceded it was designed for synchronising 8, 9.5 and 16mm film to sound projector; this most probably ran at 4.8ips. (One of our forum members has an example - can he help?)

The Baird TRS1 which followed - an entirely new deck - had optional speeds to customer choice, but this was aimed at industry/science/military rather than cine.

Barry
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Old 24th Dec 2011, 11:28 pm   #10
LXSTEIN45
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Default Re: Cine film synch - 5ips Motek

Hi Paul I am certain my grandfather had both versions, I am also certain I have seen tape with the holes and remember wondering what that was all about! I should still have the lot somewhere I will try to have a look after the christmas holidays Thanks for the info..

Quote:
Originally Posted by wd40addict View Post
Barry, I think Scophony also did a 7.2/4.8 ips version of their machine.

Lx, there are 2 types of synchrodeck. The earlier mechanical ones have the tape laced round an idler and the projector connected via a flexible shaft. A differential gearbox is used to compare the relative speeds and its output shaft is used to drive a switch which adds extra resistance into the projector motor circuit.

The later 'electronic' units have a reed switch fitted inside inside the projector to give a pulse per frame. It is used in conjunction with specially punched tape which has 18 (or 24) holes per 3.75 (or 7.5)". Tape and film can now be compared on a frame by frame basis and any difference used to alter the projector speed.

The Synchrodek was designed by a chap called Harry Garlick, and sold through his Craven instrument company. I believe he also used to own a chain of radio & TV shops.

I'm assuming it's the electronic version you have?

Regards,

Paul
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