Hi, Shai and Michael (and Michael from off-list),
I am here wrapping Christmas presents for my family...and figuring how
to deal with 17 microphones (9 wireless) for the church Christmas
Pageant Friday afternoon at the 3 and 5 PM services.
Anyway, this is a complex issue and is addressed to some degree in my
paper from the ARSC Journal.
My paper on tape degradation that was originally presented at the Audio
Engineering Society's 121st convention in October 2006 in San Francisco
was published in the ARSC Journal in the Fall of 2008. It is available here:
However, this discussion is equating SSS with back coating.
What I think I know is:
(a) Almost all SSS tapes also have back coating.
(b) Not all back-coated tapes exhibit SSS.
(c) Charlie Richardson claims that removing the back coating will
restore the tapes. He can discuss his findings in greater detail. I
can't speak for him or his patented process which I have never tried to
(d) The chemistries of the mag coat and the back coat may be similar or
different, depending on the tape.
(e) The precise chemical makeup of the tapes is unknowable at this point.
(f) The degradation trajectory relating to basic chemistry,
out-of-control processes (i.e. out of spec tape) and storage conditions
is impossible to know at this point.
(g) It appears that at least some manufacturers of some tape types
substantially changed the tape chemistries while maintaining the same
"model number". This is best documented by Benoit Thiebaut in his
testing of video cassettes for Presto Space.
(h) We think that polyester polyurethane binders were introduced about
the same time back coating was introduced, so there may be no
(i) Some archives (I believe Screensound Australia) interleaves paper
leader with back-coated tapes so that the back coat and mag coat are not
in direct contact.
(j) While the analogy may fail, have you ever seen an electrostatic copy
(like a Xerox) that has spent a long time in direct contact with a vinyl
binder? It's enough to make one wonder, at least.
(k) Some polyester-polyurethane compounds do a good job of breaking down
when exposed to moisture, especially at elevated temperatures.
(l) Bradshaw did enough work to disprove that the chains re-link when
baking as it just doesn't happen in a filled matrix.
So, that's off the top of my head in five minutes...there is no simple
answer and I doubt we'll ever have something as easy to use as a "pool
test kit" for determining the likelihood of future SSS failure. If it
says Ampex 406/407/456 on the box/reel and there is no reason to
disbelieve it, bake before winding.
I was also asked off-list about the composition of the back coat and I
suggest the answer is really (e), above. Yes, carbon black is in many of
the back coats to drain off static, but the "bad actor" here is not the
carbon black but rather the binder chemistry. Also, I've never seen a
back-coated audio CASSETTE tape. Has anyone?
I have some SM911 that is going bad--I'm not certain it's SSS or just
shedding. I forget if it's BASF or EMTEC.
Here is a list of degrading tapes that I _attempt_ to keep current.
I've been asked to do work on some Sony PR-150--pray for me.
On 2010-12-22 2:13 PM, Shai Drori wrote:
> It's a good argument, but has it been tested. Has anyone tried to
> store a back coated tape without it's back coating to see the
> difference? If I remember correctly (where is Rich Hess when you need
> him) the SSS was first discovered in ampex 400 series, but it was the
> new binder they used. I don't see how that is affected by the back
> coating, and why doesn't it affect all back coated tapes. I have many
> different tapes with back coating, some of them almost 30 years old by
> now that play like the day I bought them. Maxell XLI, BASF pem468,
> BASF dpr26, emtec 911 (not 30 years old). To put the blame on the back
> coating just because if is from the same era. It should have sown up
> in all back coated tapes. What am I missing?
> On 12/22/2010 8:47 PM, Michael Biel wrote:
>> On 12/22/2010 2:27 AM, Shai Drori wrote:
>>> I have many tape that are back coated that show no SSS. In my
>>> experience there is no connection whatsoever.
>> But how often have you found non-backcoated tapes with SSS?
>> Mike Biel [log in to unmask]
>>> On 12/22/2010 8:46 AM, Michael Biel wrote:
>>>> The one saving grace of 8mm is that I don't think I have come
>>>> across a backcoated tape in this format. So if there is any truth
>>>> to SSS being a reaction to backcoating, that reduces that problem.
>>>> Mike Biel [log in to unmask]
Richard L. Hess email: [log in to unmask]
Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
Quality tape transfers -- even from hard-to-play tapes.