I received a query from a gentleman in Europe about 1.875 in/s 4-track tapes. He was frustrated in finding a good machine for transferring them. Apparently, they have many of these tapes. Here are my suggestions.

Perhaps the easiest answer is to find a Studer-Revox C274 with low speed options. They were made.

Two other options. (more…)

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…)

I receive many tapes that use very creative methods of securing the end of tapes to reels. Some don’t do it at all. Most 1/4-inch tapes are secured as shown below. Sadly, the superior Zebra tape is no longer available. This is the traditional crepe-paper type of tape sold for the application. The picture below should explain all.

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.

The question seems to regularly arise on mailing lists and chat rooms about Dolby and dbx plug-ins. I don’t think it will happen and I added that comment and some hopefully helpful operational hints to my noise-reduction page, here.

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.

We have recently completed our second audio tape restoration seminar.

We had three great attendees. One of them, Andy Kolovos of the Vermont Folklife Center shared these comments:

I want to thank you again for the workshop. I’m certainly still assimilating stuff in my head, but it was terrific. I learned so much… Through these workshops you’re doing the archival field a huge service. The ability to tap into your experience and take what we learn back into the world with us enriches everyone. Because you are willing to share your knowledge, skill, and passion with those of us who love these audio resources, work with them on a daily basis and are eager to learn all we can about their care, more of the aural heritage of the world will survive into the future. Your generosity is wonderful! Thanks again!

You can see the brochure for our November 2005 seminar here.

Comments from the November 2005 seminar are in the brochure  for the May 2006 seminar.

The first three of the four days we were together about 13 hours a day (including dinner at various restaurants) and we didn’t stop talking audio. We covered a LOT of ground and the questions and discussions were great.

While the Ampex Mastering Equalization is well documented on this site and at the MRL site, and standard equalizations are detailed at the MRL site on page 3 of this document, I am always amazed when I discover additional, supported tape equalizations. Certainly there have been proposals for alternate equalizations. Jay McKnight has published a paper (here) about this. This post is about something different.

Teac Corporation, with their X-2000M reel-to-reel tape recorder included a button called “Extra Efficiency” to be used with then-new tapes that had double the coercivity of standard reel-to-reel audio tapes. This changed the recording equalization (and the bias and possibly the reference levels) to better make use of the new tapes to improve the overall sound.

What was fascinating here is not that they used the IEC standard equalization of 35 μs at 15 in/s, which was standard in Europe, but that they also invented their own standard and used 35 μs at 7.5 in/s as well! Not content with that, they invented yet another standard of 50 μs for 3.75 in/s.

The NagraMaster and StellaMaster equalizations are also non-standard and were probably the most widely adopted equalizations after AME, but who knows how widely used this Teac EE equalization was and who knows what tapes are in archives that had this equalization incorrectly applied.

I have been informed that it was only intended for the consumer market.

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.

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.

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…)

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.

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…)

\”Noise Reduction\” is a potentially confusing topic, partially because it has come to be used to mean two different things.

1. 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).
2. 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.

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…)

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…)

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.

Thanks, Jim, for pointing out this site that offers repair notes and replacement parts for VCRs.

http://www.fixer.com/

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.

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…)

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.

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…)

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…)

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…)

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…)

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.

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.