Corey Bailey

Audio Engineering

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Neither I or my company has profited in any way from the people or organizations mentioned in this article or elsewhere on this site. The opinions expressed herein are mine alone and do not reflect upon the people or organizations mentioned in this article. Some background First of all, I want to be very clear; In this article, I am talking about polyester base audio tape only. This would exclude all acetate base audio tape. Acetate base audio tape, most likely, will not benefit from the processes described in this article. In fact, you can possibly harm or do permanent damage to acetate base audio tape by lubricating it using the material and the procedures described herein. Acetate base magnetic film is another animal entirely. The acetate base used in magnetic film is much thicker (about 5 mils in the US, compared to acetate base audio tape which is about 1.5 mils thick) and the oxide layer applied to magnetic film is much thicker as well. I began researching lubricants when I was the Director of Sound at MGM Studios. This was about 1993 and our Sound Transfer room was coming across some Reel-To-Reel audio tapes and magnetic film that needed help to play properly. Some wouldn’t play at all. Most of the acetate base magnetic film suffered from a condition known as ‘Vinegar Syndrome’ but a small percentage had other problems that affected it’s playability. The magnetic film that fell into this category usually appeared to have a translucent white ‘milky’ substance on the oxide. The audio tape, on the other hand, was suffering from the oxide being soft and sometimes sticky. I talked to everyone that I could think of and all of those that were suggested. From Dr. Andrew Lazare of the National Media Labs, I learned the term Binder Hydrolysis and of the relatively short life span of magnetic media in general. I also learned of the patent filing by AMPEX Corp. regarding the baking of polyester audio tapes. The patent filing by AMPEX however, it didn’t address the issues with magnetic film that we had observed. John Bonner, the Chief Engineer of Warner Bros. Studios, located in West Hollywood CA, was experimenting with the use of talcum powder on magnetic film. Although talcum powder did help, it was messy and would clog the play head every few hundred feet which, would require numerous stops and starts to get through a reel of magnetic film plus, the amount of editing it took for a reel. I decided to experiment with lubricating the oxide of the media that was suffering from playability issues. I used to say that I had tried everything from Alcohol to Xycote (pronounced ‘Zee-cote’). I did find a few chemicals that worked. Alcohol being one of them and Marie O’Connell seems to have perfected the system using alcohol for audio tape playback. Alcohol will damage acetate base media so, it was out. That said, I used denatured alcohol to treat mold on polyester base audio tapes and I observed no ill effects. Some others that appeared to have positive effects were; Decamethylcyclopentasiloxane (D5), Filmguard, Jojoba oil, several silicone based lubricants, Last tape preservative (Tape Last) and Xycote which, is no longer made. My favorites were D5, Filmguard and Tape Last. Walter Davies, the inventor of Tape Last, introduced me to that product. Regarding the chemicals tried, I have no idea of their reactions with the chemistry of magnetic media or the long term affects which, was a consideration. Walt Davies assured me that Tape Last had no adverse effects on any kind of audio tape. In fact, he noted that Tape Last would enhance the shelf life of audio tape when treated. Filmguard was developed for motion picture film and works well on magnetic media. However, Filmguard leaves an oily residue. Last tape preservative is the only one that is made specifically for audio tape, evaporates quickly (like alcohol and D5) and the only one to address storage of the media after its use. The only storage history that I have on Last tape preservative is from some of my own tapes that I treated in 1998 and they show no adverse signs from having been treated. Those tapes have been stored in a closet on an upper shelf at room temperature. Recently, I revisited those tapes and made higher resolution transfers. I was pleasantly surprised to find that the tapes that suffered from Sticky Shed Syndrome and were treated with Tape Last, had fared very well. I simply re-treated them and they played without having to be baked. The only downside to Last tape preservative, that I know of, is that it is expensive. Particularly in the manner that I use it. Assessing a polyester base reel of tape for Binder Hydrolysis The first thing you will need to do is determine if the tape is suffering from Binder Hydrolysis (Sticky Shed Syndrome). This subject is also covered in my article: “BAKING AUDIO TAPE” The first thing I do with 7" reels (and smaller) is to insert a pencil into spindle hole and un-spool a few layers by hand. The tape should un-spool freely. This will tell you if the layers have the tendency to stick together. If you are dealing with a 10-1/2" (NAB Hub) reel, you will, most likely, have to mount the reel on the tape deck. Hopefully, the reel brakes on the tape deck will be disengaged, allowing for easy un-spooling of the tape. I have a couple of TEAC (Brand) NAB hub adapters (TEAC Part # TZ-612) that have a metal flange at the base which, allows them to mount to an NAB hub off the tape deck. Then, I can use a pencil threaded through the spindle hole to un-spool a few layers of tape the same as smaller reels. If you are concerned about the tape being on the floor, use a clean empty bucket or wastebasket to catch the tape as you un-spool it. If you do have to mount the reel on your tape deck, you can use the other reel to take up the slack. When I check audio tape reels on a tape deck, I will thread the tape directly from one reel to the other, avoiding the rest of the transport entirely. Know that sometimes layer-to-layer adhesion won’t rear it’s ugly head until you are at the last few wraps near the end of the supply reel. This problem most often occurs on reels with smaller center hubs (5” Reels, 7” Reels, etc.). This is why you need to pay attention to how the tape comes off of the supply reel until the very end. If, you suspect that layer-to-layer adhesion is present, STOP and consult a professional. Solving layer-to-layer adhesion can be tricky and remediation is best done by someone who knows how to deal with the problem. Often, baking (done properly) is the answer. If any of the oxide has come off and stuck to the back of the adjacent layer, it's ‘game over’ for that section of audio tape. Once you have convinced yourself that layer-to-layer adhesion is not a problem for the first few wraps, back-wind the tape onto the reel, mount the reel on your tape deck, and attach about 4 feet of leader to the head end of the tape. The type of leader (Paper or Plastic) is a matter of individual preference. Leader has several benefits; It allows for thread-up and run-up to speed on a transport before the beginning of the tape to be transferred passes across the play head. Consumer decks tend to have shorter tape paths and some were quite good at recording modulation to the very end of the tape. Leader also keeps the end of the tape protected at the outer edge of the reel and protects the tape from the unevenness of slotted hubs at the center of the reel. Eventually, leader will be applied to both ends of the tape. Once leader is attached to the outer edge of the tape, with the tape threaded up, play into the tape for about 30 seconds. Stop the tape deck and disable the transport (As though you are going to edit the tape). With the tape deck in STOP mode and the tape threaded up, rotate the reels back and forth by hand. There should be no resistance except for the reel brakes. No tendency for the tape to stick to any of the stationary parts of the tape path. Now, pull the tape away from the transport and observe all of the stationary parts of the transport (heads, guides, idler arms, etc.). There should be NO evidence of any oxide build-up on any of the stationary components. With the tape pulled away from the transport, clean everything that comes in contact with the tape. Use the purest alcohol you can find. Medical grade alcohol is best, if you can get it. Isopropyl alcohol can be found that is 99% pure. Rubbing alcohol that you get at the drug store usually contains a certain percentage of water and any kind of water is generally not good for the tape or the tape deck. Inspect the Q-Tips or cloth that you used for any oxide residue. Presuming that you have a very clean tape path, play the tape for about 30 seconds again. While the tape plays, observe how it comes off the supply reel. There should be no tendency for the tape to stick to an adjacent layer. Listen to the tape while it is playing past the heads (put your ear up close to the head stack). There should be no squealing or any suspicious sounds of any kind. Stop after 30 seconds or so, rotate the reels back and forth by hand (again) to check for any signs of sticktion. Pull the tape away from the transport and inspect all of the stationary surfaces (heads, guides, idler arms, etc.) for any sign of oxide deposit. Clean the entire tape path again and yes, inspect the Q-Tips or cloth that you used for any oxide. Some discoloration of the Q-Tip is normal. Particularly after cleaning the pinch roller(s). By now, you have played about a minute or more of the tape and should not have observed anything out of the ordinary. It is at this point that I will back-wind the tape to the beginning and lubricate the entire length of the tape. When I have finished with the lubricating process, I will attach a leader to the end of the tape and I am ready to begin the transfer after a rigorous cleaning and inspection of the entire tape path. I will often transfer side B first to avoid the unnecessary rewinding of the tape even though, on my particular tape deck, the tape only comes in contact with ball bearing surfaces for any operation other than playing the tape. If you are not using a lubricant, you can simply spool the tape from one reel to the other (carefully) and attach a tail leader. The tape deck that I use for this process (An Otari MTR-15) has been modified so that the tape itself only comes in contact with rotating bearing surfaces in any mode other than play. Even the tape lifters have been sleeved so that the sleeves act as rotating bearings. I will only use the Fast-Forward/Rewind functions to position the tape prior to transfer. Fast-Forward and Rewind functions are accomplished using the ‘shuttle’ mode with the tape threaded around a reversing idler, away from any stationary parts of the transport. Some tape decks, such as the Studer 80 series, are designed with only rotating bearing surfaces that come in contact with the tape for all operating modes other than play. Lubricating analog audio tape Once you have determined that the tape is not suffering from any kind of binder hydrolysis, you can move on to the lubrication process. Using rubber gloves or food prep plastic gloves (They’re much cheaper), Fold a 4”X4” piece of Texwipe® and wet both sides thoroughly with lubricant. I use Texwipes because they don’t shed (known as lint free). You can also use Pellon® (available at a yardage store) or any cloth that won’t shed lint onto the oxide or backing. Fig. 1 I use the “shuttle mode” on my tape deck for this process. If your tape deck does not have a shuttle mode, you can simply bypass the head stack and shuttle the tape directly from one reel to the other, lubricating the tape in the process. (Fig. 2) You will need to tape one of the idler arms so that the tape deck transport is in the ON position (Also Fig. 2). Using the play mode to turn the reels will probably be the safest. Your fingers, holding the cloth, will determine the hold-back tension during the lubrication process. This is a learned operation so I would suggest some practice if you are going to use this method. Using a non-shed fabric will not harm the tape while you become practiced. I would recommend practicing on a section of blank tape if possible. You can also use an 8MM film editing machine, if you have one. Using an 8MM editing machine, you would simply thread the tape directly between reels, avoiding the editing assembly entirely. Same goes for the practice advice since one hand will be cranking the reels. Fig. 2 For all mechanisms While shuttling the tape, periodically apply more lubricant to the cloth (tape oxide side) using an eye dropper or a syringe designed to apply liquids (Not a medical syringe with a sharp needle!). As to how often to apply more lubricant, it’s all a learning process and it depends on the speed of the tape passing through the cloth or by the applicator. I would apply a drop of lubricant every couple of seconds with the tape traveling at shuttle speed (about 3-5 times play speed). Obviously, the faster the tape speed, the more often lubricant will need to be applied. Since lubricating the tape using this process takes two hands, you will need to stop and apply more lubricant because one hand has to act as a reel break or using a hand-crank mechanism such as a film editor. Overlapping sections of the tape with lubricant is not a problem. Once you have lubricated the tape end-to-end, Attach a section of leader to the opposite end of the tape. At this point, you are done and can play the tape. Presuming that you started with side 1, you can simply flip the tape onto the supply reel and start the transfer. Know that you will be starting with side 2, if it’s a quarter track or a two track mono. Otherwise, it will play backwards. This saves rewinding the tape. Caveat; Although I have used the previously described process many, many times, the process I now use for lubricating audio tapes involves a custom built, stationary felt pad (Fig. 3). I went to the stationary felt pad method because it was somewhat faster (I have transfered a lot of tapes) and it is more of a hands- free operation. If the tape is in poor condition and/or the backside needs to be cleaned, I will use the method described above. Fig. 3 There is a considerable amount of useful information at the Last Factory website. Return to TOP of page © Corey Bailey Audio Engineering