Re: [Avid-L2] Re: HDCAM tape lifespan...

The slivers get collected by (if I remember correctly) a tape path pad.
We're talking about microns here, so it's more like fine hairs. I believe
there is a sensor that is also fine enough to detect a previously cut
tape's width. The tape path pad starts out white, and in routine
maintenance is the first thing to get replaced. The last Sony tech I worked
along side explained that the ruby cutter is many thousands of dollars, and
the tape path pad is a few bucks, and that few bucks replacement saves
potentially years of life on replacing other parts down the path.

If you're familiar enough with the sounds of these decks, you can hear when
the tape path pad comes in contact with the guides, as it makes a repeating
click-and-whirr when it's engaged. I believe it's also connected to a head
pad which lightly cleans the back side of the rotating drum, so you'll hear
this click-and-whirr sound repeatedly when there are a lot of tape errors.

This is all information I gleaned from techs years ago, so it may be
slightly off from 100% accuracy. But the concepts are solid.


On Fri, Apr 26, 2013 at 8:04 AM, john@digitalcut.com <john@digitalcut.com>wrote:

> **
>
>
> Where do the "slivers" go?
>
>
> On Apr 26, 2013, at 2:06 AM, "johnrobmoore" <bigfish@pacbell.net> wrote:
>
> > That's very interesting. I had just figured the contact of the spinning
> heads was burnishing down the tape smoother. What element on the tape
> changes so the tape deck recognizes a non virgin tape? I'm amazed I'd never
> heard about this specific feature.
> >
> > --- In Avid-L2@yahoogroups.com, Mark Spano <cutandcover@...> wrote:
> > >
> > > I think that is true of Sony decks but only after pass 1. When you
> load a
> > > fresh tape into a Sony Digi or HDCAM deck, there is a ruby cutter that
> > > slices off the tiniest slivers of tape prior to head wrap. Sort of a
> tape
> > > guide and path insurance. Once that has been done, the machine
> recognizes
> > > previously sliced tape and doesn't drop the cutter in.
> > >
> > > DVW and SRW machines are the Rolls Royce of our profession…
> > >
> > >
> > > On Thu, Apr 25, 2013 at 2:57 PM, johnrobmoore <bigfish@...> wrote:
> > >
> > > > **
> > > >
> > > >
> > > > I'd heard over the years sense we got away from analogue recording
> formats
> > > > and went to recording digital data on the tapes, around the D2 days
> and
> > > > certainly with digibeta, the tapes actually got better performance
> after
> > > > use. The theory was the heads passing over the tape actually
> smoothed out
> > > > the surface of the tape which made for better performance. I would
> imagine
> > > > this would not be something that you'd ever really see on screen but
> has
> > > > more to do with the magnetic coercivity of a smoother less bouncy
> surface
> > > > on the heads. I can't say this is a fact but it makes sense to me. Of
> > > > course damaged tape from a bad transport is another story.
> > > >
> > > > --- In Avid-L2@yahoogroups.com, Tim Selander <selander@> wrote:
> > > > >
> > > > > Yep, that's the info I'm hoping for, how many times can a tape
> > > > > reasonably be recorded -- though the shelf life info is good to
> > > > > have too!
> > > > >
> > > > > I found a pdf put out by Sony that said HDCAM SR tape is good for
> > > > > an impressive 50 uses with no loss of quality. SR is a completely
> > > > > different formula than 'just' HDCAM... but I wonder if durability
> > > > > is similar.
> > > > >
> > > > > Tim Selander
> > > > > Tokyo, Japan
> > > > >
> > > > > On 4/26/13 1:12 AM, Terence Curren wrote:
> > > > > > I think he is more concerned with number of times over the heads
> as
> > > > opposed to age of tape.
> > > > > >
> > > > > > --- In Avid-L2@yahoogroups.com, "Tom McDonnell" <ltr54@> wrote:
> > > > > >>
> > > > > >> Not sure how if this is any indicator but I have SONY brand
> BETA SP
> > > > and Beta
> > > > > >> Oxide tapes over 30 years old and 15 year old SX tapes that
> play back
> > > > like
> > > > > >> the day I recorded them.
> > > > > >>
> > > > > >> Tom McDonnell
> > > > > >> Cinematographer/Operator
> > > > > >> Weisscam Hi-Speed Tech
> > > > > >> Los Angeles, CA
> > > > > >> New Orleans, LA
> > > > > >> 818-675-1501
> > > > > >>
> > > > > >
> > > > >
> > > >
> > > >
> > > >
> > >
> > >
> > > [Non-text portions of this message have been removed]
> > >
> >
> >
>
> [Non-text portions of this message have been removed]
>
>
>


[Non-text portions of this message have been removed]



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