Why 'Baking' Damaged Reel-To-Reel Tapes Renders Them Playable Again (arstechnica.com) 55
An anonymous reader quotes a report from Ars Technica: Reel-to-reel tapes are experiencing a resurgence of interest among audio buffs, but they are prone to degradation, which has been a topic of active research for many years. It's well known that applying heat can often reverse the damage sufficiently to enable playback, usually by baking the tapes in an oven. Now scientists at the US Library of Congress have determined precisely why this method seems to work, presenting their findings earlier this month on the American Chemical Society's SciMeetings online platform.
The primary culprit for the degradation is known as "sticky shed syndrome," in which the binders used in a magnetic tape to hold the iron oxide casing to the plastic carrier deteriorate. They form a sticky residue that can damage both the tape and playback equipment. [...] [E]xperiments showed that when a degraded reel-to-reel tape is heated, the sticky residues melt back onto the bulk polymer layer, rendering the tape playable once again. That's why 130F is the sweet spot for baking degraded tapes; it's the melting point for the residues. "If you go any lower than that, nothing is going to happen," said project leader Andrew Davis, a polymer chemist who works in the LOC's preservation research and testing division. However, he also found that there is no single component that accounts for tape degradation, and the sticky residues don't just form on the binder layer.
"This research also confirmed what we heard from audio technicians, that thermally treated tapes that were wound on reels reverted to a visibly deteriorated condition within a few weeks," said Davis. "Surprisingly, we found that when our small unwound test samples of tape were thermally treated, they appeared to be optically fine even after weeks. Clearly being wound has some effect on the tapes." That is the next stage of research, and Davis actually set up a range of samples with different treatments that he was monitoring right up until shelter-at-home policies went into effect in the Washington, DC, area. He hasn't been able to return to his lab to check on them but is hopeful that, once the lockdowns lift, there will some intriguing experimental results on that score. Beyond that, Davis hopes to extend his experiments to enclosed magnetic media, such as cassette and VHS tapes.
The primary culprit for the degradation is known as "sticky shed syndrome," in which the binders used in a magnetic tape to hold the iron oxide casing to the plastic carrier deteriorate. They form a sticky residue that can damage both the tape and playback equipment. [...] [E]xperiments showed that when a degraded reel-to-reel tape is heated, the sticky residues melt back onto the bulk polymer layer, rendering the tape playable once again. That's why 130F is the sweet spot for baking degraded tapes; it's the melting point for the residues. "If you go any lower than that, nothing is going to happen," said project leader Andrew Davis, a polymer chemist who works in the LOC's preservation research and testing division. However, he also found that there is no single component that accounts for tape degradation, and the sticky residues don't just form on the binder layer.
"This research also confirmed what we heard from audio technicians, that thermally treated tapes that were wound on reels reverted to a visibly deteriorated condition within a few weeks," said Davis. "Surprisingly, we found that when our small unwound test samples of tape were thermally treated, they appeared to be optically fine even after weeks. Clearly being wound has some effect on the tapes." That is the next stage of research, and Davis actually set up a range of samples with different treatments that he was monitoring right up until shelter-at-home policies went into effect in the Washington, DC, area. He hasn't been able to return to his lab to check on them but is hopeful that, once the lockdowns lift, there will some intriguing experimental results on that score. Beyond that, Davis hopes to extend his experiments to enclosed magnetic media, such as cassette and VHS tapes.
Beautiful! (Score:4, Interesting)
https://thumbs.worthpoint.com/... [worthpoint.com]
Glad to hear they're experiencing a resurgence.
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Re:Beautiful! (Score:5, Interesting)
They were somewhat popular in the Eastern Block, in the 70s. Cassette players were nearly impossible to get without hard currency, but the Russians were making some half-way decent reel to reel players. I think they were called Romantic/POMAHTUK (in 2020, Slashdot still cannot display Unicode, i.e. no Cyrillic)
I had a Grundig portable cassette player, and that was considered the apogee of luxury. I had bartered a case of melons for it with a German tourist, who could not be bothered to fix what turned out to be a bad solder connection. Finding cassettes was very hard. Many 80% of what I had were Western pre-recorded cassettes which came with music that I did not case about, that I would record over.
And I was recording from reel to reel and vinyl, practically always. I do not remember ever recording from another cassette directly, because I did not get along with the only other guy whom I knew had a cassette player. It was funny, because that Grundig was the only music player we could take to class trip, and many people in my class had one cherished cassette that they would bring, despite not having any way to play it themselves. And those cassettes were duplicated with a reel to reel as a intermediate step.
The funny part is that when I last went back home in 2016, that Grundig still worked. It was over 40 years old.
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Reel-to-reel players were strangely a part of an underground resistance to state-sanctioned culture. The speed with which the tapes travelled across the country was mind boggling.
https://www.cbc.ca/radio/ideas... [www.cbc.ca]
"In the Soviet Union during the 1960s, young iconoclasts waged a musical battle against the banality of state-sanctioned culture. Subversive poet/musicians known as "Bards" were recorded at secret house concerts, and reel-to-reel audio tapes shared through a clandestine network. Simon Nakonechny uns
8-tracks and Cassettes are not immune! (Score:5, Informative)
My father was a kid in the '30s, and he never had a reel to reel. Vinyl to 8-track to cassette to CD was his Hi Fi experience. Vinyl was the winner at home, and 8-track for the car. I was a kid in the 70s and never saw one, except in computers.
ALL tape formats, whether open-reel or inside a cassette or cartridge, are vulnerable to this form of failure. So your dad's 8-tracks and cassettes are hardly immune. In fact, 8-tracks, even when they're not left in the sun on car dashboards, die because they're an endless loop and the glue that holds the metal foil splice that signals the track change has a tendency to fail... and the lubricant on the tape might even exacerbate the failure of the binding. 8-tracks were marginal at best when they were new; most machines of the day basically knocked their heads out of alignment four times with each album. But they were designed for car audio at a time when a good car sound system was a 5x7" speaker in the dashboard and road noise drowned out the tape hiss.
The Philips Compact Cassette (a cassette, to most people) was designed for dictation machines where sound quality was not a design criteria. It's a miracle of our technology that they ever sounded good enough for things like the Sony Walkman to happen.
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The Philips Compact Cassette (a cassette, to most people) was designed for dictation machines where sound quality was not a design criteria. It's a miracle of our technology that they ever sounded good enough for things like the Sony Walkman to happen.
Indeed, though tape quality got better and chromium/metal tapes became available to consumer's in the early 80's.
The issue with cassettes mostly being noise levels and secondary unaligned heads. The frequency response is usually just fine, all over the range. Hence, the quality of the walkman mostly determined the listening experience. Cheaper walkmans adding even more noise to the tape hiss, and jitter. The better quality walkmans had dolby and better filtering in general, making it totally acceptable and
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Of course these days we have bluetooth and memory cards, but those options suffer from practical issues (hassle connecting phone, hassle searching an album in 15GB of music instead of swapping a disc or cassette, ofc your mileage may vary).
I have an iPod classic 6th Gen in my car. It only leaves it when I want to add new music to it. It carries an entire CD collection. I paired it with Windows Media Player and an add-on called MGTEK. This allows me to set up and add playlists. iTunes would allow you to do this as well but Windows Media Player lets you create automatic playlists which are much more flexible (iTunes may have caught up by now).
This allows me to select any album, artist, or playlist on my 8" entertainment Uconnect system in
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Come you guys! Please leave your geek card at the door on your way out. Reel to reel tape was the best bang for the buck in the 70s compared to cassettes and 8-tracks although I had both of those as well.
Scotch-classic had the less tape degradation in my experience and we used to try all kinds of tapes.
Reel to reel really rocked back then with regards to sound reproduction quality and it also had become cheap by the 70s. At least, digital recording with check sums or what not are now 100% degradation proof
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Reel-to-reel had the highest quality, but also the highest price by a large margin. An RTR would be several times more expensive than a decent cassette deck. Same for the media.
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I tend to disagree. Back then, I paid $650 for my Toshiba reel-to-reel deck and Akai had some in the same price range. A friend of mine bought a Nakamichi casette deck for $1800 which had about the same audio quality. Keep in mind that high performance cassette decks with matching audio quality were new technology back then, hence the premium on the price in order to pay for R&D while reel-to-reel was a pretty well established technology available at a relatively lower cost. Reel-to-reel also occupied
Priceless Recordings, Beautiful Machines (Score:5, Interesting)
I was a kid in the 70s, and while reel-to-reel was on its way out by then, I still remember seeing them as parts of my friends' parents' hi-fi setups. They were beautiful pieces of equipment.
The machines were, and still are, beautiful. Good ones were usually pretty expensive and represented the state of the art in their day, like a flagship smartphone or laptop computer now. Even obsolete, you can see the quality and the beauty.
But the real problem is the recordings. It's not just stuff like home recordings off the radio, it's original masters of albums. The Beatles early BBC stuff was recorded on Ferrograph machines [museumofma...ording.org] (I love that name, think about what it means). God only knows what the tape formulation was; iron oxide, for sure, but what were the binders?
Most Slashdotters will be familiar with cassettes moving the tape at 1-7/8 inches per second. 7-1/2 inches per second was common in home audio. 15 inches per second in professional/studio audio use was fairly slow! At those speeds, as the tape plays, the oxide breaks free from the binder and blocks the head gap pretty quickly. Slowing down the tape and digitally replaying it faster might help, but it doesn't change the fact that A Day In The Life is a lot of tape at 15IPS - and a it's distance, not speed, that really clogs the head gaps. 5 minutes and 35 seconds is 418 feet of tape at 15IPS. No matter how quickly or slowly you play it, you could tie one end to the balcony railing of a 42nd floor apartment and the reel would still be unwinding when it hits the sidewalk below. And that's A Day In The Life, not something crazy long!
Now you add video recording with high-velocity spinning video heads to tape with flaky backing, and you're going to have a real problem playing this media down the road. You need the machine, stable tape, and someone who actually knows how to do it.
With commercial video formats far before VHS, there aren't many people alive who know how to maintain and run an Ampex Quad machine [youtube.com], for example. And with that, it's the end of countless hours of video recordings since the dawn of VTRs in the 1950s - Dr. Who, Coronation Street, WKRP. Life-altering news events, triumphs and tragedies. This is akin to losing our literary history because no one knows how to read.
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God only knows what the tape formulation was; iron oxide, for sure, but what were the binders?
I'm pretty sure I read in an audiophile magazine back in the 1970s that they used children's tears.
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Playback speeds from studio tapes has caused some issues with remasters over the years. There was a recording studio in the UK in the 1960's that had not calibrated one of their reel to reel decks for several years and it was recording at a slower speed than was the standard.
I remember getting a remaster of a Procol Harum CD and noticed the pitch being higher than it was on the vinyl copy I had. I also discovered that the tracks were all several seconds shorter. But the cover stated the original times.
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LOL he doesn't know that analog formats have essentially the equivalent of infinite bit depth resolution and infinte sampling rate compared to purely digital formats xD
LOL he also doesn't know that software engineers spent years trying to digitally emulate the tonal qualities of vinyl, analog tape, and tube amplifiers, because aesthetlcally and artistically they're considered desirable qualities xD
Sure am glad I'm not a millennial xD
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He doesn't understand sarcasm and mockery, LOL
Wendy Carlos (Score:5, Informative)
Synthesizer Pioneer, Physicist, Electronic Engineer, Composer, Photographer, and Raconteur Wendy Carlos has a wonderful article on her site explaining all this, and her adventures in restoring some old multitrack master tapes of her original "Tron" soundtrack. Definitely worth a read (as is her entire site!) :
http://www.wendycarlos.com/bak... [wendycarlos.com]
Enjoy!
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I first heard of this technique when I read about the Tron restoration on her website. Good to know how it works.
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Tron reminds me that I'd love for something like this to be discovered for laserdisc. Tron is well preserved but there are a few things on LD format that are otherwise lost and the discs are dying fast.
I've had this done (Score:5, Interesting)
I acquired the master tapes to a local duo who'd been performing in pubs in Brisbane. They'd taped and mastered some performances, and released it on cassette, circa 1987.
When my cassette started to show signs of stretching, I contacted the duo and asked if they'd released it on CD.
I received 2 Ampex reels in the post, with a note that said "go for it". So as a matter of curiosity, I took them to the original recording studio and asked them to capture the tapes to CD. Cost me AUD$160, which was explained as 2 hours of an engineer's time to bake the tapes and run them through ADC and output to a CD. I sent copies to the duo and gave some out to friends who'd been to the live shows. Well worth the money to preserve some of Brisbane's live music heritage.
https://www.facebook.com/pages... [facebook.com]
https://www.grevilleastudios.c... [grevilleastudios.com]
Sadly, one of the venues where it was recorded was badly damaged by fire 2 years ago:
https://www.abc.net.au/news/20... [abc.net.au]
The Broadway was one of the best pub music venues in Brisbane. Sunday sessions - go there for lunch and settle in for an afternoon of music, pool, beer, and laughter.
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+1 initiative
+1 responsibility
Not really a new discovery (Score:1)
Don't keep them off reel (Score:1)
Not sure if anyone else does remember but I have a vague recollection that "storing" tape off-reel becomes extremely flammable over time. Typically this happened when someone tipped a box and just stuffed the tapes back in.
Not sure, I was thought that from an old fogey when I was a whippersnapper myself and now I'm an old fogey too.
Surely (Score:2)
if an oven works, a microwave would be quicker. Quicker and betterer.
I've had this done too (Score:4, Interesting)
The story I heard was that the 456 tape which was popular for recording was never intended to be an archive tape, but it had better sound quality which is why everyone used it.
I had a project I recorded in 1988, then back in the 2000's had it transferred to CD. Melted the plastic reel - I think the temperature he used was higher, maybe 180F.
I've got a few projects I still need to do this with.....
Even more fun is when DAT tape stretches and becomes unreadable. I'm not sure there's anything you can do about it!
What the Buddha said about impermanence!
Conversion to degrees C (Score:2)
That's why 54C is the sweet spot for baking degraded tapes.
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You sir, are wrong. 327.594K is the best temperature to cook them at.
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Farenheit : Asking humans how hot it is
Celsius: Asking water how hot it is
Kelvin: Asking atoms how hot it is
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Farenheit : Asking americans how hot it is
Celsius: Asking water how hot it is
Kelvin: Asking atoms how hot it is
There, fixed that for you.
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Wendy Carlos told us 22 years ago (Score:4, Interesting)
That was 22 years ago. Wendy Carlos is the one who brought us Play Bach and Play Bach 2000, tought us what the well-tempered piano sounds like if it is not well-tempered, and brought us the film music for "A Clockwork Orange", "Shining", and Tron.
So it's nice to see this warmed up 22 years later.
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Cost (Score:2)
Davis actually set up a range of samples with different treatments that he was monitoring right up until shelter-at-home policies went into effect in the Washington, DC, area. He hasn't been able to return to his lab to check on them
Progress has been slowed. This will cost lives in more important areas of research, and general technical progress.
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And I reckon the lab is closed and nobody else is there - he could certainly go back and be safer than staying at home!
Similar issues for magtape (Score:4, Interesting)
I helped pull Pluto occultation data off of of NASA tapes obsolete tapes for my friend's astronomy masters. He couldn't find tape drives that could read the old low density format, except one that I knew was being decommissioned within weeks. They were already degrading, but we were able to read most of them. There are significant amounts of analog and digital data being lost as the readers are falling out of fashion and falling out of support, it was why I spent so much time tracing irreproducible human experimentation data to updated media, buying new digital media out of my own pocket and revising the backup tools to support much more efficient multi-tape formats.
Welcome to my world. (Score:3)
I have a back catalog of 1/2" mother tapes recorded on a Tascam 38 (8 channel open reel), mostly on Ampex 456, one of the affected tape brands (Ampex 499 and 3M 226 are affected as well). Pro audio people have known about this binder problem for three decades, as well as the convection oven cure. A friend in the same situation bought a food dehydrator on Amazon with a circular 11" chamber, perfect for a 10 1/2" reel.
Even if you do manage to remediate the binder problem, unless you've stored your tapes in a climate and humidity-controlled vault you can kiss anything above 10kHz goodbye after a few years.
Now, here's a conundrum: I have audio cassettes the same age as the 1/2" mother tapes, stored in the same sub-optimal conditions, but nearly all of them have retained more high end. None have a flaking problem. My end-of-night rough mixes from 1985 sound better than the source tapes.
You would think going digital would be a remedy for this, but what do you do with a 400k single-sided Mac formatted floppy disk from 1986 that has all your old MIDI sequences? Or 16-bit PCM audio recorded on a VHS videocassette?
Writing notes on manuscript paper is still the most permanent record.
k.
Offgassing (Score:2)
Surprisingly, we found that when our small unwound test samples of tape were thermally treated, they appeared to be optically fine even after weeks. Clearly being wound has some effect on the tapes.
My guess is that the (probably Mylar) substrate, or the binding formulation, or the reels themselves, are giving off gases with solvent properties. I've seen similar things happen when two incompatible plastics are held in contact for extended periods - one seems to start dissolving the other. With the tapes not wound the gas dissipates before it can soften the binders.
Other posters have noted that cassettes from the same era as the reel-to-reel tapes are holding up just fine. It would be interesting to kno
Boston liner notes (Score:2)
IIRC, in the liner notes for Boston's third album ("Third Stage"), Tom Scholz mentioned he ran into this problem (this was in the mid-'80s, mind you, and Scholz had a thing for doing everything in analog). He had a "one of a kind" mix of a song which sat on a shelf for ten years and adhered to the tape transport when they went to master the album. He said the fixed it by smearing lubricant goop on the tape while playing. Good times. I bet he wishes he knew the baking trick now.
Next up.... (Score:2)
Can they now research why blowing on a Nintendo cartridge makes it work again?
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Floppy disks? (Score:2)
Has anybody tried this with old floppy disks? It might be fun to treat some of the old 8" disks I have and get my old CP/M machine working again.
{^_^}