LISTSERV mailing list manager LISTSERV 16.0

Help for ARSCLIST Archives


ARSCLIST Archives

ARSCLIST Archives


ARSCLIST@LISTSERV.LOC.GOV


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

ARSCLIST Home

ARSCLIST Home

ARSCLIST  June 2016

ARSCLIST June 2016

Subject:

Re: Analysis of failing tapes - What do you want tested?

From:

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

Reply-To:

Association for Recorded Sound Discussion List <[log in to unmask]>

Date:

Wed, 1 Jun 2016 20:27:10 -0400

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (78 lines)

Hi, Corey,

Thanks for the kind words!

You can help if you have any of the tapes that are shedding shards of 
mag coat by sending small samples. I will have a shipping address in a 
few days. Also samples of similar tapes from the same project that don't 
have the problem would be useful.

More comments below under your questions.


On 6/1/2016 2:28 PM, Corey Bailey wrote:
> Hi Richard,
>
> Thank you for taking on this project. If there is anything I can
> contribute from the Left Coast, please let me know.
>
> Three questions immediately come to mind which could lead to some testing:
>
> Why do some audio tape formulations seem to last the test of time and
> other formulations are (almost) guaranteed to be SS? Generally, those
> tapes that are guaranteed to be SS are much newer formulations.

In order to make room for more magnetic particles, as I understand it, 
more aggressive binder material was used (the idea was to have more 
active magnetic domains and less glue). At the time (1970s), BF Goodrich 
sold a product called "Estane" I believe. (I am doing this from 
memory--I looked into it back in 2008 and it went nowhere). This was a 
family of products and there were also other, similar products. They had 
the magic characteristics needed.

Have you ever noticed some "polyurethane" coated tables, especially at 
restaurants have gone sticky? I believe that is the degradation of the 
polyester polyurethane and the lowering of its glass transition 
temperature, brought on by constant washing. I don't think it's left 
over Coke from the last patron.

> Does the back-coating of those tapes that are back-coated contribute to
> tape degradation? There has been some testing , mostly by Charles
> Richardson, that suggests that the back-coating may lead to SS over time.

I believe there has been other testing of this hypothesis, but I do not 
know the result. There are tapes which go sticky without back-coating, 
but it is conceivable that the back-coating can be a catalyst.

> Why are we now seeing evidence of SS with digital audio (and some DV)
> tapes? These formulations and manufacturing procedures are completely
> different than analog audio tape.

Are they really? By "completely different" are you referring to ME 
(Metal Evaporated) tape? I believe MP (Metal Particle) tape is still 
coated with a binder and that binder has gone sticky. I have seen both 
1/4-inch Digital Audio and DAT tape from Ampex, both bearing the part 
number 467 which have been rendered playable by baking. It would not 
surprise me if Ampex made this tape with chemically related binders to 
the analog audio tape, but with different size particles and coating 
specifications if it is MP tape, which I think most of the reel-to-reel 
DASH tape (at least in 1/4-inch) is.

We also had issues where some Mitsubishi DASH tapes could not play and 
we tried to get them into cold playback, but no one could do that. When 
that was happening (almost a decade ago now), everyone was afraid of 
baking digital audio tape. At the time, I suggested that stick-slip 
(even if you didn't hear a squeal) could be the culprit making the eye 
pattern close and the "bit slicer" fail to properly read enough bits.

I hope this helps,

Cheers,

Richard
-- 
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.

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

November 2020
October 2020
September 2020
August 2020
July 2020
June 2020
May 2020
April 2020
March 2020
February 2020
January 2020
December 2019
November 2019
October 2019
September 2019
August 2019
July 2019
June 2019
May 2019
April 2019
March 2019
February 2019
January 2019
December 2018
November 2018
October 2018
September 2018
August 2018
July 2018
June 2018
May 2018
April 2018
March 2018
February 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017
July 2017
June 2017
May 2017
April 2017
March 2017
February 2017
January 2017
December 2016
November 2016
October 2016
September 2016
August 2016
July 2016
June 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006
April 2006
March 2006
February 2006
January 2006
December 2005
November 2005
October 2005
September 2005
August 2005
July 2005
June 2005
May 2005
April 2005
March 2005
February 2005
January 2005
December 2004
November 2004
October 2004
September 2004
August 2004
July 2004
June 2004
May 2004
April 2004
March 2004
February 2004
January 2004
December 2003
November 2003
October 2003
September 2003
August 2003
July 2003
June 2003
May 2003
April 2003
March 2003
February 2003
January 2003

ATOM RSS1 RSS2



LISTSERV.LOC.GOV

CataList Email List Search Powered by the LISTSERV Email List Manager