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ARSCLIB  October 2016

ARSCLIB October 2016

Subject:

Re: [ARSCLIST] Scotch 206 issues

From:

"Richard L. Hess" <[log in to unmask]>

Reply-To:

ARSC Library and Archives Discussion List <[log in to unmask]>

Date:

Fri, 7 Oct 2016 17:50:38 -0400

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (178 lines)

Hi, Jonathan,

Welcome to a long ramble full of speculation and few contract facts, but 
some possible ideas that can help you narrow this down.

Jonathan showed me this off-list prior to posting here.

While I am monitoring this new development, I must confess that 
"investigating" might be a bit hopeful. Right now, we have two 
diametrically opposed perspectives, one from Southern California and the 
other from Israel, both noted by extremely competent tape restorers.

We also have some good things to look into.

I think further areas to investigate relate to exactly where the mag 
coating is separating from the base film.

The fact that you reported to me that an A80 played it with much less 
shedding further has me questioning if there is anything going on with 
the A810.

John Haley and I discussed this a bit off list regarding the different 
reel sizes in the photo. I did not mention this in my original 
conversation because I don't think it's a factor in the shedding, but 
for best performance takeup reel mass and moment arm need to be as 
matched as possible.

What I might do if the tape can survive it is library wind the tape onto 
a large-hub 7-inch reel, then rewind it onto a second large hub 7-inch 
reel, then play it onto its original 5-inch reel. I would never use a 
10.5" takeup reel with anything smaller than a 10.5 inch reel on the 
supply side. Too much difference in mass and inertia.

Also,when winding the tape on the A810, you can easily thread the tape 
after it comes over the two large rollers directly, bypassing the head 
assembly completely. If I recall correctly (I don't have any A810s 
here), there is about a quarter of an inch between the tape and the top 
of the head cover...more room with the machine in the current condition 
without the head cover.

Malcolm made an astute observation and in reviewing the shards they do 
look as if they are coming off the edges of the tape. As a point of 
reference, on my A80s and Sony APR-5000s, many of my head assemblies are 
single head reproducers. I see that your A810 is a timecode head 
assembly, which means there are three extraneous heads touching the face 
of the tape.

If the shedding is coming from the edges, I would look for grooves worn 
in the ceramic erase and timecode heads (esp. erase) that might be 
catching the edge. I would also look at the non-rotating guides. It is 
possible that something got missed even with a thorough cleaning in the 
corner of a guide that is attacking the edge.

If the shedding is in the centre of the tape, I would look for little 
hooks on the heads. It is possible that there could be a chip in the 
ceramic/ferrite erase head gap that is scoring the mag coat. I don't 
know. Something could have adhered anywhere along the tape path that 
doesn't rotate.

Anyway, please keep us posted if you can refine any of your observations 
or if you find anything.

The different sources of manufacture having completely different results 
is not surprising at all. Dr. Ric Bradshaw told me when he was involved 
in moving the IBM tape manufacturing facility from Colorado to Tucson, 
it took about a year of fine tuning (and he almost always fine-tuned 
AFTER obtaining hard scientific data) to make the Tucson plant work well.

<soapbox>

So putting together all of these unknowables--Indiana University is 
doing the right thing. While it may be late for this tape, doing a mass 
digitization of campus wide tape resources was a very wise choice and 
should serve as a model for other institutions.

</soapbox>

Cheers,

Richard

On 10/7/2016 13:03, Malcolm wrote:
 > Hmmm... the pictures don't look like shedding to me. It looks like
 > stripping. I've seen tape do this when the tape manufacturer's slitter
 > is mis-set or goes off spec. Then the first guide on the reproducer
 > strips off the offending extra width because the tape will be slightly
 > too wide to fit through the guide. This can be especially prevalent on
 > high tape tension machines.

On 10/7/2016 14:01, Aaron Coe wrote:
 > Hi Jonathan,
 >
 > For what it’s worth, there was a thread about Scotch 206 back in 
April of this year discussing extreme cases where the mag coat 
completely separates from the substrate.  Here’s a pic I took that shows 
a section with shedding: http://goo.gl/id4pNu
 >
 > Based on that thread, this appears to be a newly discovered issue 
that I believe Richard Hess is currently investigating.
 >
 > If you can search the email archive, look for the thread "Tapes with 
shedding mag coat”, otherwise you can search here: 
http://listserv.loc.gov/listarch/arsclist.html



On 10/7/2016 15:32, Corey Bailey wrote:
> Hi Jonathan,
>
> Like any magnetic audio tape, analog or digital, it will all come down
> to the storage conditions the tape was stored in over time. In my
> experience, here in Southern California, Scotch 206 has been extremely
> stable. Shai Drori has had just the opposite experience with 206 in
> Israel. Factory slitting issues can be detected by observing the tape
> running through the transport at very slow speed. Since you show the
> tape on a Studer 810, try playing a short section the tape at 3-3/4IPS
> and observing it. Slitting irregularities can often be measured with
> calipers. If slitting irregularities are the problem, I can give you
> some hints on how to get the best transfer possible, either on or off-list.
>
> If SS or SBS are not evident, you can try lubricating the oxide side of
> the tape. I use TAPE LAST form Last Factory. Richard Hess uses D-5 with
> good results. DO NOT scrape the tape across the stationary tape lifters
> under any circumstances. The exception would be PLAY mode where the tape
> lifters are not involved but the tape is coming into contact with the
> heads and guides. For handling, (fast-forwarding, rewinding, etc.) the
> tape should come in contact with bearing surfaces only. Obviously, there
> are a lot of possibilities here so, to a great extent, I'm spitting into
> the wind.
>
> Cheers,
>
> Corey
> Corey Bailey Audio Engineering
> www.baileyzone.net
>
> On 10/7/2016 8:21 AM, Richardson, Jonathan Carrithers wrote:
>> Hello,
>>
>> I accidentally posted to the ARSCLIB list this question so apologies
>> for the cross post.
>>
>> Hoping someone can help with a problem that we have been having with
>> one particular Scotch 206 tape. Links to photos below:
>>
>> Photo
>> 1<https://drive.google.com/file/d/0B4OPruHNUu42VzdrMUZIc2M4bFk/view?usp=sharing>
>>
>>
>> Photo
>> 2<https://drive.google.com/file/d/0B4OPruHNUu42QXdPa3lEZG9DR28/view?usp=sharing>
>>
>>
>> As you can see there is some extreme shedding. Has anyone ever
>> encountered this with Scotch 206? It is not historically a SSS or SBS
>> prone brand.
>>
>> Any information would be appreciated
>>
>> Jonathan
>>
>>
>> Jonathan Richardson
>> Audio Visual Specialist
>> Media Digitization and Preservation Initiative
>> Indiana University
>> 812-320-8485
>> [log in to unmask]
>> https://mdpi.iu.edu/
>>
>>
>
-- 
Richard L. Hess                   email: [log in to unmask]
Aurora, Ontario, Canada                             647 479 2800
http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.

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