couple of comments:
-the ruby piece is a tape cleaner. Mounted transversally(perpendicular) to tape travelling direction and fixed. It does not move.
-its sole role is to remove falling oxide particles before tape enters in contact with guides, fixed or moving heads and to avoid, as much as possible, clogging
-Figuratively speaking, removing falling oxide could be considered trimming, but that happens on the tape thickness, not width
-the audible gear noise is actually a video cleaning roller that's kicked in by a solenoid, whenever a tape is inserted and/or when the bit error rate becomes too high. This is a first response self-cleaning procedure the deck performs in an attempt to reduce the BER.
cheers,
BG
From: "Mark Spano cutandcover@gmail.com [Avid-L2]" <Avid-L2@yahoogroups.com>
To: "Avid-L2@yahoogroups.com" <Avid-L2@yahoogroups.com>; johnrobmoore <bigfish@pacbell.net>
Sent: Monday, January 18, 2016 5:32 PM
Subject: Re: [Avid-L2] Current Day Reliability of SR Tape Stock?
The thing you heard about the tape getting better with use isn't totally accurate. A tech from Sony that we'd hired to come and service all of our decks walked me through the tape path and explained what the little bits do. There is a ruby cutting guide at the front of the path prior to the tape going over the head. This guide is there to correct for very slight tracking differences between machines, as well as differences in manufacturers' tape stock widths. The tape as it comes down the path gets a microscopic trim. I don't remember exactly how the machine knows the tape needs the width trim, but you can sometimes hear the cutter move, especially on DVW machines (that gearshifting noise while tape is inserted or running). I am unsure if this is even necessary or valid on SR-only decks because Sony is the only SR tape manufacturer, but the 5500 should have it due to its ability to play HDCAM and DigiBeta tapes. The trims get collected by a cotton buffer pad, or just fall into the lower recesses of the machine. This pad should only need replacing about every 5000-10000 tape insertions. The tech mentioned that the bits are so tiny and there are enough guide pads in place that they should never come in contact with the drum.
Just one of the many things going on inside these machines that make them pretty magical. When the 5500 came on the market at its 100K+ price, I flinched a little, but after using it for a brief time, understood that it is a construction of nearly perfect order and worthy of its original price tag.On Mon, Jan 18, 2016 at 6:59 PM, bigfish@pacbell.net [Avid-L2] <Avid-L2@yahoogroups.com> wrote:
The stock is new tape so I've been told. To my knowledge I've never used demagnitized stock for master outputs. I have reused stock on occasion usually after reblacking. In the case of one of my recent channel error master I had actually used the stock from a cloned master from earlier in the series. It had been cloned at the facility I'm dealing with and I just insert edited over the top. I had no issues in my bay or with the Rental SR 5500. It was only at the facility they said they saw channel error. In hind sight I should have reblacked the tape but there really has been no reason from my past experience with SR tapes that I shouldn't be able to re edit over and existing show. It only had a couple passes from video output to audio layback. In fact I've been told that SR stock gets better with age as the heads spinning by actually burnish the tape surface smoother which can yield better performance. I don't know how one would actually check that but it made sense to me when I was told about it.
Sounds like your experience mirrors mine in that the format has been very solid for me with hardly any tape stock errors. An occasional interchange error I've seen. It just seemed by the dub houses explanation that they have a certain percentage of bad tapes and everyone knows this I had been living in fantasy land as I've had little to no issues for the last 10 years.
---In avid-l2@yahoogroups.com, <cutandcover@...> wrote :Check your stock source. When the tsunami hit in Japan and the main SR tape factory went offline, there was a rush on SR tape here in the states. I managed to secure a bunch of new stock, which has all been fine. But I also managed to secure a bunch of de-magnetized used stock. This has been the source of any errors I've seen outside of machines being out of spec (which in my experience is so much rarer than ever before - the SR decks (5500) have been the most solid decks I've ever used). I think SR tape is so tightly packed with particles that de-magnetizing either doesn't quite get it or manages to damage the tape in spots. Luckily I haven't had to use any of this stock in critical use - and I still have a bunch of stock left over from that rush a few years ago. The industry took it upon ourselves at that moment to up our game into file based delivery for the most part. I honestly think if that flood didn't happen, the file based delivery thing would not have taken off so rapidly.On Mon, Jan 18, 2016 at 6:01 PM, John Moore bigfish@... [Avid-L2] <Avid-L2@yahoogroups.com> wrote:I've been working on a four episode series and we've had at least 3 instances of tape hits and or bad tape on the master clones. On most I could either relay the video or worst case reblack the tape and reoutput. One tape I definitely confirmed tape damage as it still showed the hit at approximately the same time code after being reblacked. To me 3 out of 4 episodes with clone issues tape hits and or channel errors would point to a faulty machine. The facility has recently had the machines serviced with new heads as needed so I'm at a loss to explain all the tape issues. In my personal experience with SR tape over the last 10 years or so I've only had a handful of damaged tapes. I've had issues with Avid punch outs causing a tape anomaly at the out point but that can be repaired with an assemble edit.The dub facility told me that "Everyone" knows there is a certain percentage of SR stock that will be bad and even the networks are aware of this. I can't refute the experience of another person or facility but that just hasn't been my experience. I was also told that bad tape stock is so common the Tape vendors will no longer warranty SR tape stock and you have to return it directly to Sony for any warranty related issue. I've never heard of this before but I'm not in the tape dubbing business.I spoke with a co worker who actually managed a dub facility from 2006 to 2012 and he said in that entire time they probably had 5 tapes that were actually damaged. So I'm curious is there nowadays more problems with SR stock than I've been experiencing? Could the EOL of SR decks contribute a lower quality of available tape stock. We are talking new stock not the used evaluated stock. I'm curious what others have been experiencing with SR tapes and also machine to machine interchange.John Moore Barking Trout Productions Studio City, CA bigfish@...
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Posted by: Bogdan Grigorescu <bogdan_grigorescu@yahoo.com>
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