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…)
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Demagnetizing tape heads and recorder parts is a ritual of magnetic recording. If any part that touches the tape is magnetized beyond a certain level it will begin degrading the tapes played on it.
While early machines may have had an issue with magnetization, most late-model machines rarely become magnetized. The source for real information on this is Jay McKnight’s Magnetic Reference Lab Web site. (more…)
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The National Recording Preservation Board has made available a new document Capturing Analog Sound for Digital Preservation. It is an excellent summary document, and we’ve added it to our information page.
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I received a cassette from a client and he complained that the previous recording was audible as well as the new recording.
There are several ways this can happen:
- The erase head can be dirty—this usually leads to high frequencies being erased and lower frequencies still audible
- The erase head can be misaligned—this often provides a partial erasure, but careful use of track selection can find a section of track with less crosstalk.
- A similar problem occurred on quarter-track reels with misaligned record heads where recordings from the opposite direction would invade the tracks for the forward directions. Again, a specially adjustable narrow head usually solves this.
- A completely non-functioning erase system—this is what we suspect happened with the current project. There were no track dissimilarities nor any other way we could find, including looking at the tape with the 8-track cassette recorder to separate the underlying, unwanted recording from the wanted one.
- A totally unrelated mechanism that may sound the same is if the microphone or tape recorder picks up a broadcast or other radiated signal and records that along with the desired signal.
We opted not to proceed with any noise gating as it would not improve the overall audio quality for listening and may actually impede transcrption.
While not a success, we were able to confirm to the client that there was no way that could preserve the fidelity of the desired sound and remove the undesired sound. The desired interview was completely intelligible and could be transcribed. It was just distracting to listen to.
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\”Noise Reduction\” is a potentially confusing topic, partially because it has come to be used to mean two different things.
- Today, it means removing noise from a recording by means of a single-ended post-production device or plug-in, such as Noise Free Pro by Algorithmix that I use (among other tools).
- Historically, the term was used for a double-ended process where the dynamic range of the program material was reduced in an unobtrusive way, transported by the noisy channel (be it tape or broadcast) and then expanded in a complementary fashion at the end/output of the noisy channel. These devices were generally referred to as companders (a contraction of compressor/expander).
When reviewing old tapes, they may be marked in various ways to indicate their noise reduction compression, or processing. As of this writing, there are no software plug-ins that accurately mimic the action of the hardware compander acting as an expander. We use actual companders from the original systems when restoring tapes made with these systems.
We currently handle nine different formats from four manufacturers and are always on the lookout for more. Most manufacturers sold a variety of systems tailored to the needs of different kinds of transmission/recording channels
See our special page under formats (click here) to see some of the information we’ve gathered about noise reduction techniques used over the years. Check back as we uncover additional formats and information.
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Thanks, Jim, for pointing out this site that offers repair notes and replacement parts for VCRs.
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There was an off-line discussion about VHS-Hi-Fi tracking and breakup in Hi-Fi playback and how to correct it. I brought Jim Wheeler into it, and he agreed to write this article. —Richard
I invented the automatic tracking system in 1976 but it is pricey. If you want to pay about $2,000 for a pro-VHS machine, you can get true auto-tracking. Manual tracking works for most tapes. If not, there was a problem with the recording VCR. Alcohol is not good for cleaning heads and tape guides. I always use Xylene and you can buy Xylene at hardware and paint stores. Do not use Xylene on a pinch roller! Have your window open when you use it. I sniffed Xylene for over 30 years and am still okay–okay–okay….I recommend using Xylene for cleaning all components in the tape path except the pinch roller. I recommend Isopropyl alcohol for cleaning pinch rollers. [Some of us are using Formula 409 on pinch rollers—it depends on the pinch roller and its application—Richard] (more…)
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You’ve been asked to digitize recordings in your collection and don’t have any idea where to start. There are several resources on this site which might be of use.
What I use is shown on my facility page. That\’s one of the main reasons it is there. If I’m using it, it’s because I like it or it solves a problem for me. If I’m not using it, either I don’t have an opinion about it, won’t spring for it, or don’t like it. (more…)
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The round-pin power cords used on older Hewlett-Packard and Dolby equipment uses a connector called the PH-163.
The round-pin power cords using the PH-163 connector come in two versions. The difference between the two versions is that the hot and neutral are reversed. The ground is always in the same centre position. (more…)
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I received a phone call today from someone who wanted my opinion on a Tascam 238 8-track cassette recorder for recording his music.
This was like the person who wanted to know about the DCC recorder for the same purpose yesterday.
People keep hearing that “analog sounds great” or that this or that format “sounds great” and they want to buy in. (more…)
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Audio levels (and their cousin loudness) has been an ongoing area of confusion and annoyances from the 1930s on. Adding digital to the mix has done little to simplify the situation.
Here we discuss some of the background and the relationship between the VU Meter, the Peak Programme Meter, and digital meters reference to 0 dBFS (Full Scale). (more…)
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I received a phone call today asking if I knew where to get DCC blank tapes. The person had purchased a used DCC machine on eBay or someplace like that because he “heard that they sound good.”
Audio mythology is growing. DCC is a perceptually coded format with bit reduction. Like MP3. Like the ATRAC system used on Minidisc. Not as advanced as MP3, probably (it’s older). Not as advanced as Windows Media (it’s older). (more…)
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This is a guest article from Andreas Weisser who runs Restaumedia in Germany. Neither Andreas nor Richard can take responsibility for the work that you do based on these instructions which are provided on an as-is basis. Any risk of using them is solely your own and not Andreas’s, Richard’s, or anyone else other than you, the person undertaking to use these instructions. If you have any questions, please contact Andreas. — Richard
This is a step-by-step guide for the removal of U-matic Cassette from a Sony VP 7040/9000 U-matic Player by hand.
1 — Turn the power OFF.
2 — Remove the Upper-Case of the video player. Use a Phillips screwdriver to loosen the fixing screws. Then pull the Upper-Case in the direction marked by the red arrows shown here in picture 1.
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I got a call today from a friend who said the hum shields on a friend’s APR-5003 were not working.
I recalled this had happened to one of my machines in the past.
Removing the cover surrounding the heads will expose the mechanism—of course the heads and pinch roller need to come off first.
Cleaning and lubricating the rods and other parts of the linkage should make all well again.
I used Zoom Spout Turbine Oil.
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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.
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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.
- 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.
- 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.
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I made this chart to show how the different standards and recommendations for media storage overlapped. Click [or save target as] for the full-size image.
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The regulatory climate and economics will support a wide variety of “wall-wart” power supplies for the foreseeable future. These are, at best, a headache to deal with. Some of the ways I’ve dealt with them are: (more…)
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This has been updated 2015-07 and now 2005-11. We ordered a new 1022 viewer from Arnold/Flexmag as the 2007 Sigma finally gave up the ghost and the 2011 Sigma that I had as a spare is not as good a performer for this application. As of the end of November, we are still awaiting a response from Sigma. Overall, I am quite pleased how well the “fresh” Arnold unit works and it appears more sensitive than the older 3M unit I had even when it was working well. This is now my top choice. It is not perfect, but fits the budget better and performs much better than the newer Sigma. It is also faster than the Sigma ever was.
Please look here, but there is still good information, below.
Two ways of seeing tracks on a tape are listed here. We’re collecting more in the comments. (more…)
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The 20 kHz bandwidth of CD audio media may cause truncation of some material. Here is an example of a small amount of energy above 20 kHz in a symphonic recording. It is interesting to note that this is a 7.5 in/s recording done on 1970s prosumer equipment. I’ve said in my presentations for some years, most 7.5 in/s tapes are well-suited to 44.1ks/s 16 bit transfers, but there are exceptions. This shows one. (more…)
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Remember, this transfer that you (or I) are about to undertake may be the last time (and hopefully the best time) that the original is transferred. Here are some suggestions: (more…)
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MINIMUM Tape Handling Requirements Checklist
This checklist is not a complete guideline. It contains only those items that experience and testing show will have an immediate or severe effect on magnetic tape. Failure to adhere to the items on this list may cause premature loss or deterioration of magnetic tapes and should be considered misuse of the medium. These are minimum handling requirements that summarize good practices. (more…)
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As promised, I will respond to some questions that are asked via email by answering here in the Blog.
One of the things I’m most concerned with is the appropriate use of digital processing in transcription for cleanup or remastering of digital archival copies. This includes both questions of when (if at all) processing beyond the actual A/D conversion is appropriate, and which are the techniques and currently available tools best suited to archival audio.
It’s a good question. To some extent, it depends on the client and the final use.
If the restoration/preservation reformatting is for an institutional client, then the first transfers should be as unprocessed as possible — at least the initial copies that are archived should be done that way. The main reason for this is that processing algorithms will always get better and they may hide some information that is useful to future researchers–information that today we consider “noise.” (more…)
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Large-scale, enterprise-class storage is using combinations of both disc and tape. LTO tape appears to be growing more than any other format.
What is described in this article is obsolete in a large part. Please see the Data Storage category for current thinking.
For those of us who are working at a much smaller scale, I have provided references on what I do for fairly robust storage on a budget. Please see these two attachments: description and map. It shows a unified (I hope) approach useful to small archives and businesses. (more…)
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It just came to my attention that computer architecture is transitioning from the PCI interface to the PCI Express interface.
This supports my contention that Firewire (IEEE 1394) and USB 2.0 are the preferred methods for connecting high-quality, high-resolution audio interfaces to computers.
While I have two RME Multifaces (the original, not the Multiface IIs shown in the link) that use dedicated PCI cards, this means that if I purchase a new computer with a PCI Express interface, I’ll have to purchase two new PCI Express interface cards for the RME Multifaces — and hope that RME makes it at the time I need it. Many users have expressed satisfaction with their Digital Audio Labs CardDeluxe.
This sounds a lot like the Zefiro Acoustics ZA-2 ISA card that is languishing in a Dell Dimension XPS PII 333 MHz machine.
My recent foray into an audio interface via IEEE 1394 was the MOTU 828 MK II. So far, I am happy and it’s finding uses in the studio as well as the remote notebook-centric applications I originally acquired it for.
I would think that a good audio interface might last longer than a good PC, so consider this approach.
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Many pieces of equipment with cross-headed screws actually have Pozidriv screws rather than Phillips screws in them. This is especially true of Japanese equipment. [EDIT 2007-11-26] Or are these yet different JIS screws? See the updated post about this here.
I bought a set of Hozan [JIS] drivers, but now that I’ve learned that PB makes them [maybe] (see tools article) I’ll buy any additional ones from them. Pozidrive screws have “tick” marks between the slots–or should.
Here is an interesting explanation of the different screw heads in the context of cabinet/furniture making.
After some testing with both Phillips and Pozidrive drivers, it seems that some/many of the inexpensive screws that come packaged with home hardware-type items are non-descript and perhaps don’t meet either standard!
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One way of loading C-0 cassettes is to unscrew the shell and drop the old tape into the new shell.
I have found that reloading using a modified cassette machine is much faster and easier. The following images should explain the process:
Splice one end of the original tape into the C-0:
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We have been wondering just how far we can push the Sony APR-5000 capstan servo system, so we ran a few tests using an external oscillator feeding the reference port. Unlike Ampex, Otari, and Studer machines which use an external reference of 9,600 Hz; the Sony machines use an external reference of 19,200 Hz.
We found that the APR-5000s did not run reliably below 1.88 in/s — and that is achievable with a -50% varispeed already. It didn’t matter what the base speed was.
The APR-16 (cousin of the APR-24) did not run reliably below 3.75 in/s. But the good news was that we could bring 15 in/s down to 3.75 in/s using the external reference source. We were also able to run the APR-16 at 60 in/s, but takeup tension was a bit low.
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The 108 memory locations for storing setups is a real feature of the APR-5000 series tape machines. The APR-24 manual alluded to this but did not provide any instructions.
I have the only APR-16 that Sony ever made, but it is essentially the same as an APR-24. My APR-16 is running firmware version 5.01.06.0.
It appears that there are a total of 18 total preset locations in the APR-16 (and presumably the APR-24). (more…)
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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.
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