The Training for Audiovisual Preservation in Europe (TAPE) Project has just published an excellent Audio Tape Digitisation Workflow document here. It is authored by Juha Henriksson of the Finnish Jazz & Pop Archive and Nadja Wallaszkovits of Phonogrammarchiv, Austrian Academy of Sciences. It is aimed at the newcomer but still addresses all of the major points without being overwhelming.
reels
Studer A807 digital noise improvement
I received an email from Andrew Pearson of the British Library providing some hints in reducing noise during playback on the Studer A807 tape machine. He would be interested in hearing from people who had other ideas and people who had either successes or failures attempting his techniques.
A solution to reduce spoking in old acetate tapes
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.
Five historic standards now linked from the history page
About two years ago, I asked the EBU to make available a copy of their historic document, Review of existing systems for the synchronisation between film cameras and audio tape-recorders and they complied, making it available on their website.
I asked the National Association of Broadcasters about their Cartridge, Cassette, and Reel tape standards as well as their Disc standard and they gave me permission to post these standards at my website.
These five standards plus some other articles of historic interest are available here in the history portion of this website. I hope that you find these of use in unraveling some of the challenges that old media present.
Another way to identify a tape with Sticky Shed Syndrome (SSS)
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.
Kodak Durol triacetate tape with bad vinegar syndrome
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).
Sony APR-5000 head assembly problem
I was having slightly intermittent connections on one head assembly on a Sony APR-5000 and was concerned as to the cause because the 78-pin head connectors are essentially unobtanium and a headache to change.
As I installed and de-installed the head, I got to thinking that the connector might not be positioned correctly (i.e. perhaps the wrong hardware had somehow found its way into the connector mounting system.
When I measured the bottom (oriented as if the head were mounted in the machine) face of the connector mounting flange referenced to the bottom of the mounting posts (using a straight-edge across two of them), I discovered that, indeed, this connector was recessed about 25 mils (0.025″) further into the head assembly than several other ones. Adding a 25-mil thick washer should solve the problem.
This is posted in case you’re scratching your head with a similar problem. This is something I wouldn’t have immediately thought of. I don’t know if this was caused by aftermarket work or if it perhaps represents a manufacturing error.
Updates posted for “winding tapes for long-term storage”
There was yet another discussion about winding tapes for long term storage. This time it was on the Society of American Archivists list. While it was focused on VHS tapes, where it was decided that it was more important not to leave the tape in the middle with active content exposed, some discussions of the mechanics arose and I have added them as comments to the original post, which is available here.
Dangers of old tape recorders for playback; using the elevator head
We are currently working on some un-published tapes for a major Canadian folk artist. We have a 7.5 in/s 2-track stereo recording that was one of (if not the) first studio recording of this artist from circa 1972.
At some point, this tape was played on a 1/4-track machine that injected hum onto the left channel. Here’s what the magnetic viewer showed:
Long-term stability of different batches of Ampex 456 – a guest article by Gary Galo
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:
IASA TC04 Guidelines on the Production and Preservation of Digital Audio Objects available online.
The International Association of Sound and Audiovisual Archives (IASA) has released their landmark Guidelines on the Production and Preservation of Digital Audio Objects as a free web (HTML) edition, available here.
I provided some information for the listing of tape equalizations, and I find the compiled table (here) most useful.
Thanks to Kevin Bradley and the IASA team for their work in making this available. If you want a PDF copy, join IASA and it’s available.
Track Configuration page updated
I added a Track Configuration page to the resources hierarchy in the sidebar at the right. This points to other resources on the web to provide further insight into the various analog audio track configurations. There is also a brief note there about the variation in the two-track, half-inch format. These differences are minor, but they could be a source of some problems under some extraordinary circumstances.
This page was updated 2012-01-05 to provide track widths on higher-density audio multi-track formats.
A link to the Studer track dimensions page was added 2012-01-06.
Speed variation with unmatched reels
I received an interesting question from a European tape user with whom I frequently correspond:
“Is there any speed variation when playing a tape with different hubs on the supply reel and take-up reel?”
And I replied:
You raise an interesting question. The easiest answer to this is simple:
There is a risk of speed variations throughout the reel if the tape tension varies throughout the reel.
followed by the corollary:
This effect is made worse if the condition of the capstan / pinch-roller system is degraded.
and
Some capstan / pinch-roller / constant-torque systems handle this better than others.
Playing full-track mono tapes
About ten years ago, when I transferred the oldest tapes in the United States as part of the Mullin-Palmer collection, my good friend Don Ososke pressured me to use a full-track head for the project. I had started transferring these full-track tapes with a Woelke NAB stereo (two 80 mil (2 mm) tracks) head and recording both channels. When I obtained a Nortronics full-track head, the difference was night-and-day. The full-track reproduction sounded fuller, smoother, and quieter. There were no tracking problems to speak of that would cause azimuth wander large enough to create a “flanging” or “phasing” effect of in-and-out high-frequency loss.
Capturing both directions of a half-track mono tape
It is possible to capture both directions of a two-sided half-track mono tape in one pass.
The critical factors are:
- Azimuth
- Direction
- Polarity
Playing a squealing reel of Sony PR-150 tape using D5 (Decamethylcyclopentasiloxane)
Today I worked on a batch of five Sony PR-150 7-inch reels recorded at 3.75 in/s in one direction, two-track mono. One of the five reels showed marked shedding during fast-wind/rewind (to get the original reel as takeup and to check the tape pack). Four of the five reels played fine. This one squealed horribly. I ran the tape up and back over the dispenser and then fixed it in position for running the tape over it during the playback session. Once again, D5, Decamethylcyclopentasiloxane, CAS Number 541-02-6 comes to the rescue. The lovely thing about D5 is that it evaporates.
Is this better than cold playback? I don’t honestly know. Both work. This is easier if there is no reel machine standing by for cold playback (which there was not today). I keep a Nakamichi MR-1 in the refrigerator so it is ready to go when I need it. The Studer A810 I put in the fridge did not like it. The capstan motor seized up AND the heat output overwhelmed the refrigerator’s capacity to cool. I suspect the APR would also overwhelm the refrigerator’s capacity. Also, it is much easier to lubricate a reel than a cassette.
Stripped hex head screws
The 2 mm hex head screws that hold panel modules and blanks on Studer A810s are easily stripped by slightly worn hex drivers. Studer used 2.5 mm hex head screws in the later A807, perhaps aware of this issue. Using PB drivers from the start will reduce the possiblity of this happening.
There are essentially two choices when this happens:
- Slot the screw with a Dremel rotary tool and a small cutoff blade and use a slotted screwdriver to remove the screw.
- Use some sort of Ez-Out screw extractor.
When I was confronted with this situation recently and I didn’t have an EZ-out of the correct size to bite into the screw without drilling, I grabbed a T10 Torx driver and gently tapped it into the screw head. I pushed in hard while starting to turn and the screw came out.
Introduction
I have made a variety of static pages for my tape restoration Web site, but thought it was time to add a more user-friendly, article-based location to discuss various topics, tools, tricks, and techniques that I have come across in various ways.
What is easier to use than ready-made BLOG software, so I guess Richard is finally Blogging!
I hope you like this and find it of interest. Please let me know of any changes or topics you might like addressed.
Enjoy!
Note: This post has been put in every top-level category because it appears that a post is needed in each top-level category if the sub-categories are to be visible.
Note 2: The Tips & Notes blog and the Formats & Resources static pages of this sub-site replace the Tips and Resources static pages on the Web site. And, there is integrated searching across both the blog articles and the static pages.
Shedding Japanese 206 at Indiana University
In October, 2016, Jonathan Richardson of the Indiana University Media Digitization and Preservation Initiative contacted me and sent these two photos:
