A few months ago, I transferred several Tonschreiber tapes which were IG Farben Magnetophonband Typ C manufactured in Germany prior to the end of 1943. These had been stored in their almost-sealed steel cans and stunk. The best description of the smell was old lemon chicken.

We know that the sealed can will accelerate the vinegar syndrome degradation. The big question is are these tapes an anomaly or the mine canary for some (or all) acetate tapes?

The composite photo below shows some of the conditions that we found. Note especially the rolled outer strands showing extreme shrinkage from vinegar syndrome.

Click for a larger image.

We were able to transfer these tapes,  but the sound quality suffered due to the unsteadiness of the tape transport. The quality of the sound was due mostly to the fact that this was recorded at 30 in/s (probably 77 cm/s) with a full-track head. Nothing beats areal density for robustness.

I have been suggesting for many years that one of the reasons that acetate audio tapes have not suffered from vinegar syndrome to the extent that acetate films have suffered from this malady is because of differing storage practices. In general, film for many years was stored in sealed cans while tape has generally been stored in cardboard boxes.

I recently came across a 3-inch reel of acetate tape, not in its original box, that showed the following pattern in the box. This tape was recorded in Fall of 1964 and the photo was taken on October 2006, 42 years later. The tape played well, considering it was originally recorded at 1.88 (1-7/8) in/s.

All of the outgassed material that was absorbed by the cardboard was no longer free to degrade the tape.

UPDATE: March 2008…Cold playback (see this article) seems to work with the two tapes mentioned in this article, 3M 175 and Sony PR-150. We’ve had confirmation from several sources who have tried it.

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

Fellow restorer Doug Pomeroy sent me a photocopy of Herman Burstein’s “Tape Guide” article from the May 1977 issue of “Audio” magazine. Robert Coe of Manchester, CT, wrote in saying “…some of these [Scotch 175] tapes have developed a high frequency chatter or squeal which is mechanical and can be stopped by rubbing the tape with a light coating of talcum powder. The squeal only occurs on the Scotch 175 tape even when used with several different brands of tape machine.” Burstein replied, “Yes, I’ve heard other complaints about squeal, sometimes involving Scotch tape which is not surprising in view of 3M’s large share of the market, but yours is the first complaint about 175 tape.” He went on to say that another 3M tape exhibited this but it was limited to the batch and 3M replaced it.

We do not recommend the talcum powder approach as it overall has proven to be a bad idea since it gums up the machines and increases spacing loss more than other solutions.

Doug is currently having a joyous bout with 175 but Art Shifrin apparently has a proprietary mechanical fix to the tape deck that allows playing 3M 175.

We are researching more about 175 and hope to have updates. The use of decamethylcyclopentasiloxane (D5 or cyclomethicone) has had mixed results with 175 and Sony PR-150, another known squealer.

In several instances, we have seen binder adhesion to the back of next layer in the tape pack. When the tape is unwound, a portion of the the binder adheres to the layer it was resting on, and is pulled off the layer it was supposed to be on. It looks like this when held up to the light:

There are many possible causes for this adhesion (or pinning, as it is sometimes called). For this tape, we believe moisture intrusion and poor storage conditions contributed to the problem. It is often a problem with plastic leader tape.

Slow unwinding has reportedly helped, as has cold, dry storage for an extended period.

This tape  (Melody 169) also squealed, but we finally got an acceptable transfer. Fortunately, this was recorded on only one track, and it wasn’t the one with all the holes in this picture.

This post has been updated as: http://richardhess.com/notes/2007/03/21/soft-binder-syndrome-and-sticky-shed-syndrome/

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).

Recent work in which I’m participating seems to indicate that what we thought was happening in both instances may not be really what is happening.

For now, the continued recommendation is to bake tapes for which baking works. These include:
Agfa (pre-1990): PEM 468, PEM 469
Ampex/Quantegy (1970s-1980s): 406, 407, 456, 457
Note: Recent reports indicate that these problems may exist in tapes made in the 1990s
and later, even under the Quantegy name.
Audiotape/Capitol (early 1980s): Q15
Note: This tape may or may not respond to baking. Some tests will be conducted soon.
Scotch/3M: 226, 227, 806, 807, 808, 809

If these are squealing and leaving deposits, they should be baked (at your own risk). The Ampex patent for baking tapes can be found here.

The classic test for determining if a tape is suffering from LoL has been to bake it and see that baking fails. The assumption has then been that it is loss of lubricant. This test, however, may exacerbate the condition and it is not recommended to bake suspected LoL tapes.

Tapes which appear to be suffering from LoL include:
Scotch/3M: 175 and Melody 169 (a seconds brand of Scotch)
Sony: PR-150
Pyral: (type numbers unknown for this French tape)

We have seen cassette tapes also suffering from LoL.

There are several ways to address playing LoL tapes, but, for the moment, we are not prepared to publish anything definitive beyond Marie O’Connell’s tried and true method shown here.

Often a tape comes in for restoration that has been poorly wound or poorly stored. Here is an example:

One of the interesting things about this particular tape was it had been recently wound on a constant-tension professional machine prior to shipping to me.

We think that the entire tape had not been re-wound, allowing the higher tension wind to compress the inner core slightly, causing this cinching. After transferring the tape (which didn’t show much ill effect for its cinching), we still found it difficult to get the tape to wind smoothly on the reel.

Therefore, our current suggestion is if you find a tape like this, do not rewind it and attempt to clear up the cinching unless you are also ready to transfer the tape, as there are no guarantees that it can be wound better after unwinding.

Please see this post for an update (2008-02-15).

A client phoned me and said a cassette he was playing started to shed in his machine and he stopped and took it out. He sent it to me and as I pulled a little bit of clear leader out of the middle of the tape, this is what I found:

Notice how the complete strips of oxide exist on their own, independent of the clear “leader” to which they previously were attached. (more…)

This is the first of many guest articles here. Thanks to Marie for agreeing to share her wonderful work in playing tapes that did not respond to baking. SSS=Sticky Shed Syndrome, LoL = Loss of Lubricant
For a current list of degrading analog tapes, click here.–Richard

There has been a lot of interest in this issue recently and I’ve answered several people privately. Hopefully this location will make the work more accessible to all who are interested.

The general appearance of the Mark II. As you can see, I had the luxury of being surrounded by these great machines and so we sacrificed one with all the adaptations done by a great technician by the name of Noel McGinnity – we both agreed we still wanted it to look like an almost regular Studer! All the tubing has been adapted to withstand isopropyl alcohol and the IV drip bag does not leak.

I began working at Sound Archives/Nga Taonga Korero, which is a wholly owned subsidary of Radio New Zealand in 1994. My task was to preserve and digitize the entire NZ Composer’s collection to begin with. I was taught my skills “on the job” but was lucky enough to have the wisdom & know it all of several older broadcasting technicians at my fingertips.

(more…)

This is a general article to provide some information on the subject. More should follow.

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

There are multiple modes of degradation and it depends on the type of tape.

Acetate Tape

• Degrades through drying out (hydration has helped in some cases)
• Breakdown of the base through “vinegar syndrome” and possibly leading to total decompostion (although that has not been seen for tapes on any large scale)
• Damage from heat
• Damage from mold/fungus
• Loss of Lubricant is probably rare in acetate tapes. Few examples of it have been found.
• Freezing acetate tape (especially) is considered bad as many of the formulations included fatty-acid lubricants. Remember, this was from the 1940s and 1950s and one of the best lubricants of the era was sperm oil.

Polyester tape

• Binder hydrolysis (or sticky shed syndrome [SSS]) is the largest challenge faced with tapes from the 1970s-1990s. This can be partially reversed through incubation or heat treatment. While this link may not be complete, it is a great introduction.
• Loss of Lubricant (LoL) can be severe and can possibly be combined with binder hydroysis.
• Freezing is also not recommended for polyester tapes due to the potential of that tape also containing fatty-acid lubricants.

Obviously all tapes can suffer from mechanical damage and poor winds.

I expect to be discussing aspects of this in greater depth, but it is a complex subject and contradictory reports have been generated.