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RE: Jumpfree/ Metaspeed



Peter wrote:

>...JumpFree and MetaSpeed comprise computer controlled systems that learn the
>film transport characteristics and compensate for vertical cyclical errors
>that occur due to mechanism or film material errors. The systems establish
>these measurements by comparing the relationship between the capstan that
>is driving the film and a precision sprocket tacho that reports the films
>exact position at any point in time. ...


The "precision sprocket tachos" that came with our JumpFree Ursa Golds each 
consists of a VERY old fashioned tacho cup with 16 slots per revolution that fits into
that darn LED/sensor array in the deck plate that is so much fun to work on. I think
you have to get a MetaSpeed (or a Philips telecine) if you want a true high precision 
sprocket that has a modern shaft encoder. (such as a Hewlet Packard model with
4096 counts per revolution).

However, I am still amazed at the incredible vertical stability (for 35mm) achieved
by a factory-standard JumpFree on an Ursa Gold. For that matter, I recall a test that
we performed on a MetaSpeed with its precision tach disabled (using only the
Gold's LED array) in which we saw very little difference in vertical performance with
or without the better tach. In comparison testing, the MetaSpeed was better than 
Jumpfree but they were both in the same ball park. I especially liked the real-time
data readout of the MetaSpeed. The calculus at work behind the servo is displayed
in detail that would make Newton proud. (and maintenance engineers happy)

If only the guy who designed JumpFree was still at Cintel so that he could add a wide
range of speeds and other improvements... If only Cintel had offered factory-fitted 
MetaSpeeds before we bought 4 Golds...

Randy Reck
Encore Santa Monica