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Year: 2006

Round-pin power cords for older equipment using PH-163 connector

The round-pin power cords used on older Hewlett-Packard and Dolby equipment  uses a connector called the PH-163. I think I have enough to last me. I bought my last batch in the early 2000s.

As of 2024 these cords are becoming more and more difficult to find…but they still keep appearing in small quantities.

In April 2024, Kazuo Iwase contacted me (out of the blue) from Tokyo, Japan, saying he had just received a box of these cords. His contact information is below.

Thanks once again to Rick Chinn (In 2021), there still is a USA source. These have European connectors, bare ends, or non-molded NEMA 5-15P plugs attached. As of April 2024, this USA link is still active Use your browser’s search function (<ctrl> F) to find HP Oval.

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circa 1943 German acetate tape: anomaly or mine canary?

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.

Tonschreiber Tape

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.

Acetate tape buffered by cardboard box

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.

Box discoloured by acetate breakdown products

All of the outgassed material that was absorbed by the cardboard was no longer free to degrade the tape.

Sticky Shed & Loss of Lubricant

This post has been updated as: https://richardhess.com/notes/2007/03/21/soft-binder-syndrome-and-sticky-shed-syndrome/

For a current list of degrading analog tapes, click here.

For several years, we have been discussing the differences between Sticky Shed Syndrome (SSS) and Loss of Lubricant (LoL).

Recent work in which I’m participating seems to indicate that what we thought was happening in both instances may not be really what is happening.

For now, the continued recommendation is to bake tapes for which baking works. These include:
Agfa (pre-1990): PEM 468, PEM 469
Ampex/Quantegy (1970s-1980s): 406, 407, 456, 457
Note: Recent reports indicate that these problems may exist in tapes  made in the 1990s
and later, even under the Quantegy name.
Audiotape/Capitol (early 1980s): Q15
Note: This tape may or may not respond to baking. Some tests will be conducted soon.
Scotch/3M: 226, 227, 806, 807, 808, 809

If these are squealing and leaving deposits, they should be baked (at your own risk). The Ampex patent for baking tapes can be found here.

The classic test for determining if a tape is suffering from LoL has been to bake it and see that baking fails. The assumption has then been that it is loss of lubricant. This test, however,  may exacerbate the condition and it is not recommended to bake suspected LoL tapes.

Tapes which appear to be suffering from LoL include:
Scotch/3M: 175 and Melody 169 (a seconds brand of Scotch)
Sony: PR-150
Pyral: (type numbers unknown for this French tape)

We have seen cassette tapes also suffering from LoL.

There are several ways to address playing LoL tapes, but, for the moment, we are not prepared to publish anything definitive beyond Marie O’Connell’s tried and true method shown here.

Let sleeping tapes lie—what to do with poorly wound tapes

Often a tape comes in for restoration that has been poorly wound or poorly stored. Here is an example:

cinched tape

One of the interesting things about this particular tape was it had been recently wound on a constant-tension professional machine prior to shipping to me.

We think that the entire tape had not been re-wound, allowing the higher tension wind to compress the inner core slightly, causing this cinching. After transferring the tape (which didn’t show much ill effect for its cinching), we still found it difficult to get the tape to wind smoothly on the reel.

Therefore, our current suggestion is if you find a tape like this, do not rewind it and attempt to clear up the cinching unless you are also ready to transfer the tape, as there are no guarantees that it can be wound better after unwinding.

Please see this post for an update (2008-02-15).

Project Notes: Advanced oxide delamination of a cassette

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:

flaky_tape_01

Notice how the complete strips of oxide exist on their own, independent of the clear “leader” to which they previously were attached.

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U-Matic 3/4" Cassette Removal Procedure When Normal Ejection Is Not Possible — Guest Article

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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Loading C-0 cassettes

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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Wet playing of reel tapes with Loss of Lubricant—A guest article by Marie O’Connell

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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Binder adhesion to back of next layer

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.

Sony APR-16 Memory Locations (APR-24)

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).

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Sony APR speed experiments

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.

Is it really a Phillips screw or is it a Pozidriv screw?

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!

When is the 20 kHz limitation an issue? How big an issue?

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.

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Computer audio interfacing

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.

Analog "Warming up" of sound & the use of obsolete formats in contemporary recordings

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.

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Transfer level settings

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).

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Digital Compact Cassette — DCC

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).

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Categories dcc

Archival processing

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.”

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Magnetic Developers — Seeing the tracks

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.

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Powering Wall-Warts

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:

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Do’s and Don’t’s of tape handling

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.

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Sony APR-5000 Hum Shields not working

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.

Tape Degradation—Introduction

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.

Acetate 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.

Polyester tape

  • 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.

Noise Reduction Basics

\”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.

Project Notes: Crosstalk on a cassette

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.