This page provides a table of signal wavelengths for different speeds and frequencies. It is sometimes useful in understanding bandwidth limitations at the high end for a particular head. The first null occurs when the wavelength of the signal is about 112% of the optically measured length of the gap. A common place to set the gap length is for a 4 dB loss at the highest frequency of interest. This corresponds to the half wavelength indicated in the table below. See Mallinson, John C., The Foundations of Magnetic Recording, Academic Press, San Diego, 1993. pp 95–96.
DTRS (DA-88) Transfers now available through TASCAM
TASCAM has set up a very reasonably priced transfer service for multiple-cassette projects recorded in the DTRS format (DA88, etc.).
For more information, click here.
I cannot warrant this service, but what could be better than having it attached to the service facility. I have listed other resources on my format page.
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 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.
Source for D5 (Decamethylcyclopentasiloxane)
I have recently been looking to replenish my supply of D5 (Decamethylcyclopentasiloxane) and did not have much luck receiving replies to my email. Others have reported difficulty finding this in quantities smaller than a 55-gallon drum.
I found a promising listing for cyclopentasiloxane and when I queried the supplier, he indicated that the analysis was 97.5% decamethylcyclopentasiloxane and the balance being octomethylcyclopentasiloxane. I suspect that is more than good enough for tape work.
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.
Tools
High-quality hand tools are a must for working on high-end tape machines. I’ll discuss some of the specifics in other articles.
The tools that Studer supplied (when required) were made by PB Baumann, now PB Swiss Tools in Switzerland.
My preferred supplier (for North America) is Tool Lady. She also sells Wiha tools to complement the PB line. Barbara Christy, the original Tool Lady succumbed to cancer on April 11, 2015 after a four-year battle. Her daughter Rachel Straight has announced that she, in the guise of Tool Lady II, will continue the business.
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.
The Phone Plug—Uses and Misuses
The ubiquitous phone plug, especially in the 1/4 inch (6.3 mm) size, is extremely confusing to the uninitiated. I was at a church today where I struggled to get a video to play properly in advance of an event in a few days.
The church had a PC and two 60-inch diagonal video monitors (another story). The audio was fed to the good-quality 16-input mixer (Allen and Heath, I think) from the PC’s headphone output.
In the video, there are two places where there is speech and the music is faded into the background. When played in the church, the voice disappeared! This created some angst coupled with erroneous assumptions. I hope this post will perhaps help solve this problem for others.
The Digital Cliff and HDMI
I was at a church today where I struggled to get a video to play properly in advance of an event in a few days. There were issues with the application of a TRS phone plug (another story).
The church had a PC and two 60-inch diagonal video monitors plus a smaller monitor for the choir. There appeared to be a powered splitter/amplifier at the balcony console to split the HDMI to the two big monitors, with one cable running down each side of the church. I believe there must have been a second two-way splitter (hopefully another powered splitter/amplifier) to tap off the feed from the right main monitor for the choir monitor.
When I arrived, the PC was set up for 1024 x 768 display with the HDMI output mirroring the laptop built-in display. The laptop built-in display was capable of 1366 x 768. The slide show was a 16:9 WMV file. I tried expanding the display to the widescreen resolution and it was fine on the PC, but the monitors would not sync.
Power options for field recording
I had the first failure to capture an entire concert in my recording career. I had become complacent and considering that I had new (April 2012) Li-ion batteries for my Sound Devices 722 recorder, did not think twice about recording a concert on the approximately 50 Wh 6-cell packs. Well, one failed, and did so spectacularly without a warning. I did not notice the in-process warnings, because I do not wear my headphones during the whole concert. I try and take in the concert so that I can then see what’s missing in the studio. Here is what the after-the-fact results showed:
US Music Media Statistics
Pete Hammar and Tom Fine came across a great site detailing 40 years of music statistics in a series of pie charts for each year. I thought it might be interesting to show this as a graph:
(Click image for full-sized view)
Thoughts about 8-track cartridges…
I have just transferred three 8-track cartridges and I thought I’d share my thoughts about these transfers and what are realistic expectations for these cartridges.
Mouse alternative … the graphics tablet
When I made a 30th anniversary photo book to give my wife, I nearly killed my mouse hand working in Lightroom. Also, a mouse is a difficult way to do fine adjustments of the cursor.
Protecting the container: Heritage Building Fire Safety
While this post does not specifically pertain to audio tape restoration, it does pertain to keeping originals and copies safe, especially in heritage buildings.
This article is prompted by a devastating fire in Aurora, Ontario, Canada, where I have lived for the last 10 years and also from 1981-1983. On Friday, April 11th, there was some roofing work being done on the 135-year-old Aurora United Church. Roofers were using hot tar and allegedly some sort of open flame. Humidity is not high in the winter and we had a cold one. The church roof structure (and much of the ceiling structure of the nave) was wood. Hot tar, flame, low humidity, wind, and very dry old wood do not mix well, and the results, sadly, were predictable. The church is now a ruin. The fire department spent 4-5 hours with up to maybe 7-8 master streams running into the attic and other parts of the structure.
Voltage and power matched audio in 2014
I received an email requesting clarification on my 1980 AES Preprint about the use of voltage audio distribution vs. power matched audio distribution for analog audio signals.
The confusion seemed to be about equipment being rated for driving a 600 ohm load. Yes, most professional audio equipment will drive a 600 ohm load, but might (repeat might) lose a small amount of headroom doing so. The better reason to be able to drive a 600 ohm load is to drive long cables which might create slew-rate limiting if they load the output to the extent that they slow it down. It’s all about current. In fact, merely being able to drive a 600 ohm load may not provide enough current to drive very long cables.
Cyber Tweaking
There were a few functions that were not operating as well as I had hoped in the home network now that we have DSL and Cable again and two VOIP telephone lines, one configured per incoming service.
Since we have double NAT which is generally a bad thing, I needed a work around to fix NTP time updates that had broken. This did the trick on the main router (downstream of the modem/routers). Note that I’ve added this to the Connection Hub (DSL Modem/Router) as well.
And while on the subject of router tricks, this port forwarding scheme was suggested by TekSavvy to keep the VOIP Adapter working well on a SageMCom wired port.
Brief report on how the new camera outfit worked after three weeks of photographing on Maui
| Thanks to all who read my previous post on rationalizing my camera system. It worked like a charm. The 70-200 f/4 and TC20Eiii converter make an excellent telephoto that focuses quickly (with the range limter, especially) and the 16-85 is a step up from the 18-200. The whole trip was a good time for Mary Beth and me to relax and I had a fantastic time with the photography. For more details and some fairly high resolution images, continue reading. |  |
Restoring something approaching natural colour to a 50-year-old photograph
My wife has been putting together a slide show for the Aurora Historical Society and I’ve been helping with some of the photo cleanup. She did the difficult part of culling a couple of hundred images out of 10,000 that are sort-of organized by different people over many years. We came across this gem.
Windows 10 upgrade–a bunch of thoughts and experiences
Here is a rambling discussion of my experiences and thoughts on the Windows 10 upgrade experience. I am now happy that I’ve done it. I’m still learning about it, but work is progressing with few (if any) glitches. Cutting to the chase: a worthwhile upgrade at the right price with few downsides.
Taming Windows 10 File Explorer
Here, now you can have the benefit of a day’s research and tweaking.
Windows 10 File Explorer provides vast quantities of information that can, at times, be overwhelming.
My goal here was to simplify the interface and provide only what I needed. There was lots of good help on the Web and many options. This is what I decided to do, at least for my five machines. Fortunately, much of this is the same from Windows 7 and Windows 8.1, so there is lots of documentation out there, but it’s not all in one place. Here’s my attempt. I WILL BE USING REGISTRY MODIFICATIONS. IF YOU ARE NOT COMFORTABLE DOING THIS, THEN DO NOT DO IT. Make a backup. There are other ways of making things work if you wish to take a different approach, but I will leave that exercise to you. YOU ARE ON YOUR OWN. I cannot help you if things go awry. I have tested this on two desktops.
“All your files are just where you left them” EXCEPT the ones in AppData (Win 10 rebuild)
I had a bit of an issue with a Win10 upgrade from Win7 for my wife’s laptop. Nothing short of a full reload of Win10 would stop FileExplorer from resetting and restarting every few seconds. This did not allow me to use Control Panel, either. Settings worked.
So, it told me that it removed Thunderbird and Firefox.
It ALSO removed all the AppData files (like all of her email).
Colour repair in Photoshop and Lightroom
I was working on a media and image digitization project this spring and early summer. Some of the slides from 1960 had horrible color shifts. Here are two examples that I helped along in Photoshop and Lightroom. I did not take detailed notes on these but thought that they might provide an indication of what is possible without too much work. Obviously, other defects could have been reduced, like fingerprints, but there was an inadequate budget for this type of cleaning. Clicking on either image will bring up a larger version. I made the scans of the original slides on my Nikon Coolscan 5000ED.
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:
