Here’s some info that might be useful concerning which batches of Ampex 456 are good and which have sticky shed problems.

I recently unearthed 26 brand new 10 1/2-inch reels of 456 from 8 different batches. I checked one reel from each batch by playing them back and forth at 15ips (I only played the bad reels in one direction – that was enough!). The following batches were bad:

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I recently received two 7-inch reels of Kodak Type 31A Triacetate tape (1250 feet, Durol Base) that smelled of vinegar even before I got the envelope open.

These tapes were badly warped due, most likely, to the vinegar-syndrome induced differential shrinkage. Other factors may have been poor winding during long-term storage (I had received them after several attempts to play them on another machine). (more…)

I was interested in the progression of the Scotch/3M tape boxes over the years, especially after someone contacted me because his father was in the picture on some of the 1960s tape boxes.

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We have pulled the list of degrading analog audio tapes out of the blog postings (which age) and put this information into the Formats hierarchy under Analog Audio Tapes, click here. Please note that we have fudged the hierarchy by starting the title with a hyphen, so it sorts to the top of the Analog Audio Tape grouping, above 0.15″ cassettes.

We hope to update this as we come across more types. January 2009 was, sadly, fruitful in finding at least some batch(es) of two tapes from 1990 (Agfa PEM 526) and 2003 (Emtec SM911) are degrading. The Emtec SM911 was thought to be more-or-less immune from this disease. As of this writing, it has been confirmed that batch number B0134007 was involved.

We have just seen a modification on the Sticky Shed Syndrome (SSS) failure mode. This is a case where the back-coat of the tape is turning to powder. The oxide was brown but yet it left a black, non-sticky accumulation of powder on the reproduce head. This accumulation would drastically reduce the high frequency response of the system due to spacing loss. We did bake the tape and we’re not sure that helped significantly, although it did not appear to make the problem worse. We would NOT recommend baking these tapes in the future. Ultimately, Pellon wiping of the mag coat during transfer after several pre-wipes for the length of the tape solved this.

Agfa PEM-526 exhibited this odd behaviour. The tape was recorded in 1990.

There is also a discussion about PEM-469 showing similar behaviour here.

For a current list of degrading analog tapes, click here.

My paper on “Tape Degradation Factors and Challenges in Predicting Tape Life” that was published in the Fall 2008 issue of the ARSC Journal is now available online. Click here.

For a current list of degrading analog tapes, click here.

Teaching people how to identify tapes that are suffering from sticky shed syndrome is often difficult.

I would like to propose that a careful inspection of how the tape comes off the pack may be a good way. Please provide comments as to how it’s working for you.

The tape should come off the tape pack at a precise tangent to the tape. If the tape starts to adhere and not pull off straight, that is a sure sign that the tape needs baking.

Of course, don’t bake acetate tapes even if they show this indicator, but on the last batch of questionable SSS tapes, I’ve been looking at this and it’s a fair indicator, and it seems to show at the outer edge of the pack.

More than one “test” or “factor” is needed to be sure, but this one is looking good.

Another almost sure sign of SSS is brown oxide and black back-coat.

It appears that many old acetate tapes when played on high-quality audio recorders will suffer spoking when left in a play wind condition. I have discussed this problem here. Since posting that, I have taken one of my Racal Store 4DS recorders and removed the heads to save them from wear and now use that to re-spool any tape that shows spoking when played on a Studer A80, Sony APR-5000, or Studer A810. (more…)

I spent days trying to get Shamrock 031 to play without much success. Since this is an Ampex factory budget brand (probably non-spec premium tape) I thought that it might be suffering from Sticky Shed Syndrome. I baked it for 12 hours and it still squealed. I then tried my usually successful cold playing technique and it still squealed. Cold playing has worked successfully with 3M 175 and Sony PR-150.

I was getting rather frustrated and since it was a four-track tape and one of the techniques that is supposed to reduce squeal is to play the tape faster, I dragged out my Racal Store 4DS instrumentation recorder which has a 75,000 Hz bandwidth at 15 in/s and played it at 15 in/s and digitized it at 88,200 samples per second. After slowing it down 4x and ending up with a 10 kHz bandwidth (which I subsequently truncated to 5 kHz since there was no useful information above that, but lots of noise–same as the non-squealing portion of the real-time transfers on a Studer A810).

 

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For a current list of degrading analog tapes, click here.

For several years, we have been discussing the differences between Sticky Shed Syndrome (SSS) and Loss of Lubricant (LoL). It appears from my latest research (presented at the 2006 Audio Engineering Society’s 121st Convention in San Francisco in October) that LoL does not really factor into the equation for most tapes and that an overarching failure mode is Soft Binder Syndrome, or SBS. Sticky Shed Syndrome appears to be a subset of SBS. (more…)