Cook those tapes for future listeners: Prepping reel-to-reel recordings for archival preservation

Cook those tapes for future listeners: Prepping reel-to-reel recordings for archival preservation
February 24, 2015 Steve Hormann

akai tape playerWith the change to digital formats in broadcasting, analogue media such as the old magnetic reel-to-reel recording tape become a thing of the past. Even though there might be priceless or historic programming preserved on the tapes, today’s digital players aren’t set up to easily convert analogue storage formats. You need more than hardware necessary to connect refurbished analogue equipment, proper audio editing software is also vital for accurate reproduction. The marketplace offers a variety of software programs anyone interested in preserving collections will find useful.

None of this addresses a specific, potentially disastrous problem inherent in aging tapes themselves.

Over time, depending on storage conditions, humidity, temperature and other variables, magnetic recording tape often adheres upon itself, becoming like a giant roll of scotch or masking tape. Results can cause tape decks to play at extremely slow speeds, if at all. The tape itself may split or sheer.

Companies that originally produced recording tape, notably Ampex,  researched and found solutions to the problem known as “sticky shed syndrome.”

Industry’s tape rescue remedy involves a food dehydrator.

Food dehydrator image

The author used this off-the-shelf food dehydrator from Sportsman’s Warehouse restoring 1980s Interior Alaska live music tapes for broadcast over KUAC FM.”bake” the tapes in an oven at a specific temperature for a set time to cure the problem.

The procedure of “baking” old recording tapes in an oven at a specific temperature for a set time is detailed in a 1993 patent application by Ampex. 

In the case of the brand and size of tapes commonly used in the radio broadcast industry, a 10 1/2 inch reel would be heat treated at 130 degrees for a period of four hours. This in effect allowed the backing tape, bonding agent and magnetic recording material to return close to its manufactured state and allow for a transfer of recorded material into a digital format. Since the use of magnetic recording tapes began in earnest in the early 1950s, there is now a means to preserve many hours of historic performances along with news programming.

So as I am working my way into this field of audio forensics through internet searches beginning with the care and maintenance of  old vinyl records and 78 rpm shellac discs, I stumble upon this recipe to help me with my efforts at working with a handful of tapes that I had on hand. This did not seem out of place as I read through the technique. Considering what I was doing in regards to my other activities of record cleaning, refurbishing vacuum tube audio gear etc., using what info that I could find on other audio related collector websites.

I had my reservations when I read about the temperatures needed to accomplish the work. Subjecting brittle old tape to a desert heat bath is enough to give any acoustic hound pause. But  that old Ampex patent on the process instilled faith.

So, after clearing off the kitchen counter, making sure that I had read through the Ampex tech sheet one more time, and looking at a couple YouTube videos applying the technique, I proceeded. I loaded three 10 1/2 inch tapes into the dehydrator dialed the temp level to 130 degrees, set the timer for four hours, then left for the front room and commenced sweating.

At the end of the four hours (plus another hour for cooling of said tapes!), I placed my guinea tape on the same deck that struggled playing it beforehand. Lo and behold, notes flowed from the speakers from a live concert recorded almost 30 years ago!

To top it all off, every tape I’ve since baked “tastes” as good as originally recorded.

Steve Hormann
Steve believes in keeping the mind active. He's entering his retirement years while pursuing a degree in journalism. Working at combining old and new, digital and analogue, this senior citizen enjoys learning new technologies. Particularly when it applies to audio.

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