As well as analogue tape, at Greatbear we also migrate digital tape to digital files. Digital media has become synonymous with the everyday consumption of information in the 21st century. Yet it may come as a surprise for people to encounter digital tape when we are so comfortable with the seemingly formless circulation of digital information on computers, at the cinema, on televisions, smartphones, tablets and other forms of mobile media. It is important to remember that digital information has a long history, and it doesn’t need to be binary or electronic – abacuses, Morse code and Braille are all examples of digital systems.
Digital Betacam tapes were launched in 1993 and superseded both Betacam and Betacam SP. Betacam remains the main acquisition and delivery format for broadcasting because there is very little compression on the tape. It is a very reliable format because it has a tried and tested mature transport mechanism.
While Digital Betacam is a current broadcast format, technology will inevitably move on – there is often a 10 year lifespan for broadcast media, as the parent company (SONY in this case) will cease to support the playing machines through selling spare parts.
We were sent some Digital Betacam tapes by Uli Meyer Animation Studios who are based in London. Uli Meyer make 3 and 2 D commercials, long and short films and TV commercials. 5-10 years ago the company would have had Digital Betacam machines, but as technology develops it becomes harder to justify keeping machines that can take up a lot of physical space.
Workflow in broadcasting is also becoming increasingly ‘tape less’, making digital tape formats surplus to requirements. Another issue facing the Digital Betacam is that it records information in Standard Definition format. With broadcasters using High Definition only, the need to transfer digital information in line with contemporary technological requirements is imperative for large parts of industry.
We were recently contacted by Frank Whelan of the Comhaltas Regional Resource Centre who wanted us to digitise a recording of the Fleadh Cheoil traditional music festival in Buncranna, Co. Donegal in 1975.
Frank sent us an EIAJ ½ inch video that was recorded on a Sony High Density V-60H video tape for Helican Scan Video Tape Recorder. The tape was suffering from binder hydrolysis (often referred to as sticky shed syndrome), so needed treatment before it could be played. The tape was incubated and cleaned before the digitisation process.
The recording contains fascinating footage of solo and group performers from the biggest traditional Irish musical festival in the world. The first Fleadh Cheoil took place in 1951 and has happened every year since. Comhaltas are currently collecting archive material for every year the festival was held in order to create a document for future generations. The digitised film will go towards an exhibition and will be stored in a research facility focused on Irish traditional music.
This is an excerpt of the film that Frank kindly said we could use on our site.
Yet again bad capacitors have reared their electrolytic fluid! This time in a Grundig Video 2000 video tape player, or V2000.
Pictured above is a X2 mains film cap in the power supply of the video machine, made by Frako. This brand of capacitors are German and used in many Studer audio tape machines too which commonly have similar smoking fun such as the B67 and sometimes the A80.
A nice satisfying repair though – all Frako film and electrolytic capacitors were desoldered and replaced with 105 degrees rated Panasonics. The circuit boards on these type of machines are also well made with thick tracks so there’s little risk of lifting solder pads with this type of repair.
Other than their ageing capacitors and some dry solder joint problems these Grundig machines are excellent although as with many older domestic formats the important proprietory spares like the V2000 upper head drums are very rare new now so keeping these machines running will get harder and more expensive over time.
This format was commonly used in education and in industry and was much cheaper than the U-matic and one inch formats.
We usually see Scotch and Sony branded tape stock in this format. The Sony tape, is absolutely unplayable and dangerously so. It becomes ‘sticky’ or suffers from binder hydrolysis as Ampex audio tape commonly does. The tape will squeal loudly on any fixed guides and often stop moving around the head drum often damaging the head tips.
This tape can be restored and recovered but must be dehydrated at a very stable and constant low temperature. We’ve found this tape takes much longer than audio tape in this process and it’s also necessary to address any tape pack slip too. Custom winding machines are essential here as winding this tape on the vintage machines necessary for playback is too aggressive.
The image to the right is a tape we received and has an uneven tape pack and a small amount of mould growth too.
After dehydrating, winding and cleaning the tape and and tape pack looks more like this:
Early tape based digital formats such as DAT, Tascam DTRS and ADAT, etc are often problematic now, partly with tape issues and also reliability and spares availability. In 20 or even 10 years time these machines will be much less serviceable than the analogue tape machines of the previous generation and as a result more obsolete and a higher priority to migrate to a file based digital format.
We’ve also started to see a particularly nasty problem with some, and usually the 120 minute length, DATs. The first symptoms are a broken DAT tape usually on wind. The tape pack seems to become slightly sticky, with intermittent tension between the layers of tape and with the thinner tape in 120 lengths this can sometimes break the tape on wind.
You can see in the above image how the tape sticks slightly to the pack and then releases when hand wound. With the greater tension of a machine wind and the tape also wound around the head drum this becomes risky.
With large transfer jobs checking each DAT by disassembly is a mammoth task, but the permanent damage and / or part loss of a section of audio caused by a break is not feasible either!
We take pride in the analogue and digital video equipment we've collected, saved, repaired and restored. Below is an ever-growing list of the analogue and digital tape machines we have available at the Greatbear studio.
Lindos LA101 audio Oscillator / LA102 Audio Measuring Set
video digitising hardware
Blackmagic Decklink SP
Blackmagic Decklink HD Extreme x 2
Blackmagic Decklink Studio 4K
AJA Kona LSe
AJA Kona Lhi+ x 2
Panasonic DMR / JVC DVD recorders
Clockwise from top left: IVC 826P 1” VTR, Ampex AVR-2 quadruplex 2" VTR, Sony AV-3670 CE ½” VTR, Akai VT-110 ¼” VTR, Sony BVH-3100 PS 1” VTR
Clockwise from top left: Sony VO-9600P U-matic VTR, Philips VCR N1500 VTR, Sony EV-S700UB DAV Video8 VTR, Sony EVO-9800A & EVO-9800P Hi8 VTRs, Sony J-3 SDI & Sony BVW 75 (NTSC) Betacam SP VTRs, Sony SVO-9620 S-VHS VTR, Grundig Video 2x4 Video 2000 VTR, Sony BVU 950P U-matic VTR
Clockwise from top left: JVC PR-D1000E aka Panasonic AJ-D350 D-3 VTR, Sony JH-3 HDCAM VTR with monitor, Sony DSR-2000AP VTR, Sony HVR-1500 HDV VTR, Sony DVW-A500P Digital Betacam VTR, JVC BR-D 750E Digital S / D-9 VTR
Clockwise from top left: Inside U-matic VO-5850P; various rare replacement parts; Shibaden (Hitachi) SV620D 1/2" reel-to-reel; Adrian fixing Sony EVO-9800 Hi8; 1" C Format drum eccentricity & head tip penetration gauge
Contact us, of course! No seriously, how to transfer video to dvd or any other digital format is a very simple concept but the reality can be pretty complex. As with much mature technology, the domestic video formats and machines were often made pretty straightforward to use and hid much of the complexity of analogue video from us.
The simplest methods are to use the few machines ready made for the transfer purpose but these were only made for the most common video formats. Several manufacturers made VHS to DVD units and these can work well if MPEG2 DVD Video is the only format you require.
The problems come for the less common formats and when the tapes themselves start exhibiting physical problems.
Times are changing though and even the most common domestic formats like VHS will soon become harder to work with. While it’s still possible to buy older video machines that may work and your old video machine at home or in the attic may still work this situation is changing fairly quickly.
Very few manufacturers carry a full range of spares for their older machines anymore and often what stock they have, once sold is never remade. Even in the professional and broadcast markets companies like Sony only guarantee spares support for equipment up to 10 years from manufacture.
What this all means is that to support a range of legacy, analogue video formats as we do, constant sourcing of parts, parts machines, obsolete service manuals and older specialist knowledge is vital. This isn’t always easy or cheap and highlights one of the key issues in digitising video tape.
The Teac A3440 is a classic reel to reel tape recorder from the late 1970s, early ’80s significant in that you could use it to make 4 track multitrack recordings at 15 inches per second, the professional tape recording speed. At the time there was precious little else around at the price to do this so this machine was perfect for small bands and studios who didn’t have the wallet busting amounts needed to buy a larger format 16 or 24 track recorder.
While the A3440 isn’t the last word in high quality analogue recording it has had some significant users in the past none less than Lee Perry who’d used the earlier but similar A3340 on his Heart of the Congos album.
the problems
This machine didn’t initially look heavily used, the heads had little wear but it hadn’t been used in a long while and there was a heavy build up of tape residue on the whole tape path. The capstan was very dirty and in these cases xylene is a more effective cleaner than IPA but don’t get it anywhere near plastic!
This A3340 powered up but the right hand tension arm was hanging at an odd angle and it wouldn’t play or wind.
Time to take it apart – the fake wood sides and rear panels get removed and it’s pretty easy to see what one of the problems is.
A very nasty ‘melted’ rubber capstan belt that took a fair while to scrape and clean off with IPA.
A new belt has purchased online – Teac parts in the UK are a big pain to get hold of through the official channels and I’ve given up contacting them unless I’m desperate for a part I can’t find anywhere else.
The other lack of drive was caused by broken micro switches. When the right hand tension arm is moved up, two micro switches behind the front panel switch power on for the capstan and reel motors. As this arm can get a los of use / abuse it’s common for the micro switches to crack. Both on this example were broken as was the small plastic piece that stops the arm moving too far down.
the repairs
To replace the capstan belt:-
Remove both screws holding the capstan flywheel against the front panel.
Make sure the flywheel is cleaned of all old belt debris.
Make sure the motor wheel is cleaned of all old belt debris.
Refit new belt over small motor wheel, then flywheel.
Replace bracket remove in part 1, making sure you’ve cleaned off the old grease and regreased where the end of the capstan shaft can run.
Although not essential I took the opportunity to remove the whole capstan shaft, clean, check for wear and reoil before putting back. If you do this you will need to reset the endfloat though.
microswitches
It’s not possible or worthwhile trying to repair the microswitches as the modern equivalent that fits perfectly is very cheap. Two were purchased from Farnell and replacement is just a case of:
Unscrew and move away the control PCB to get more space
Make a note of or photograph wiring connections for switches.
Unscrew and carefully desolder the existing microswitches.
Connect wires and solder the new switches in.
The arm end stop was repaired easily with strong super glue and after many hours is still holding.
is it working?
In a word, kind of! The belt and microswitches got the deck and transport moving. It will pull tape and make a noise which is great but an annoying intermittent problem started to appear after some initial testing.
When play or wind are selected, large solenoids clunk and release the reel brakes and move the pinch wheel. This was working BUT occassionally and only in play the right reel brake solenoid didn’t move, leaving the brake on, causing the tape speed to slow, back tension to increase and wow to go crazy!
We’ve been a bit quiet since last year on our blog here primarily because we have been processing a large, ongoing audio archiving digital migration job for Mood Media Ltd
In essence audio archiving, digital migration, transfer or digitisation, whatever term you prefer, is conceptually simple: one analogue or digital format is moved to another, usually digital, format. It is in the details of this process that things can get complex – requiring experience, specialised tools and often custom-built solutions.
This job has many factors – not just attaining the best analogue transfers, but also addressing the organisation of such a large amount of 10.5″ reels, their digital management once migrated and the creation and management of metadata.
The archive, dating from the 1950s up to the early ’90s, even though it had been stored in less than ideal conditions, is in generally good condition. An interesting and often fantastic-sounding collection of recordings and music are evident all recorded at 15ips in mono, stereo and some encoded with Dolby A noise reduction.
There are specific issues with some tapes that are not uncommon with older audio tape:
Binder hydrolysis or sticky shed syndrome (SSS) has affected a significant proportion of the archive in particular Ampex branded tapes from the 1980s onwards.
Some glue used in spices from the 1980s spreads over time and tends to stick layers of tape adjacent to the splice together. This can be a very frustrating problem which rarely damages the tape permanently, but affects the tape tension on certain sections so that head to tape contact is momentarily lost and a very obvious audio glitch noticed.
The analogue side is important to get correct initially but the management of the data is critical with such a large number of reels and individual artists and tracks. Each batch of tapes would be catalogued in a .csv file. The digital audio transfers were split into individual tracks which then had to be renamed based on the data in the .csv file. This was handled by some php coding which matched the metadata supplied with the files, checking for inconsistencies then renaming the .wav files on one of our servers.
This type of customised workflow can be tricky to setup initially and find the balance between accuracy and speed but once done a smooth workflow is possible maintaining high quality, accuracy and value.
Tascam, Fostex and Yamaha sold cassette multitrack recorders in the golden days of home recording in the 1980s and ’90s. The 4 track format was especially popular but an 8 track format was also developed that squeezed even more out of the small tape width of the cassette.
We love these cassette formats and their accessibility helped start many musicians’ careers. Unfortunately one of the best 8 track machines, the Tascam 238 Syncaset also suffers from a common and frustrating problem that renders most of these machines useless over time, the dreaded direct drive capstan motor failure…
The 238 and other 8 track and high quality stereo tape decks, the 688 and 122 MkII and III, used a direct drive capstan motor for precise speed control and reduced speed variation or wow and flutter (w/f). The circuit that controls this motor fails in certain ways causing lack of speed control and in our case the capstan motor wizzing away at a crazy speed, not the 9.5 cm/sec that it should do.
This here is the culprit – you can see the attempted repairs which didn’t ultimately work.
One common failure is that the surface mount electrolytic capacitors fail or their capacitance changes to such an extent to cause speed problems. These can be changed for standard through hole caps but you do need to be very careful as the tracks are damaged very easily – good tools are essential.
The other point of failure in the circuit is the BA6304F SO16 IC – we even changed this but the motor still didn’t turn!
There was some suggestion from previous repairers that the grease at the end of the capstan flywheel hardens over time. increasing the friction and causing problems with the circuit.
This can become frustrating quickly, especially when you have a large archive of cassettes to digitise.
When we can’t repair we reluctantly do the next best thing and buy the whole replacement part but this is another exercise in frustration. Teac parts and Teac UK don’t have any european supply of this capstan motor (part no. 53700075-01) anymore as of November 2011. Interestingly about 6 months ago they did at around £60 GBP, then about 3 months ago they had one left at £160 GBP!
Lots of emails later to Teac US, Teac Canada and Teac Japan there seem to be a nice stock still on shelves somewhere and at reasonable prices UNTIL you ask them to ship to the UK when you discover they can’t do this and I’d need to go through Teac UK!!! I’m pretty persistent but I gave up finally even though some of the support staff tried to be pretty helpful.
We find support for older machines from the original manufacturers is not good generally and unreasonably expensive when you can find it. This is similar across audio and video, semi-pro and professional products. Some companies are easier to deal with and have a better parts situation than others, but stockpiling machines, parts, manuals and obsolete knowledge is the best course of action.
What we finally did that worked and was a good solution was purchase 3 Tascam 122 Mk III stereo cassette decks which use the same but a later revision of the capstan motor, (part no. 53700121-00). One machine was donated for the cause and the capstan motor removed, modified and refitted in the 238. The 122 motor has a few factory extras, such as these resistors, shown here:
You also need to solder / desolder the speed pads, to change the motor speed from 4.8 cm/s to 9.6 cm/s that the 238 needs to run at.
It’s also a good idea once you’ve got the capstan motor apart to clean the old grease from the seat, check the end float which can be adjusted using the screw shown on the left and apply new grease to the capstan end.
Put it all back together – be careful to solder the wires to the motor to the correct pads – they’re different on the 122 and test… Ours worked almost perfectly.
As the transport hadn’t been used for a while the reel motor would intermittently stop as if sensing the tape end. This can sometimes be loose counter belts but on the 238 it’s a digitial counter. We cleaned up the leaf switches on the transport top and also sprayed a small amount of deoxit into the inside of the reel motor. A bit more use and it finally worked to spec…
Digital formats are great and the ease of access and distribution that an Audio CD and a Video DVD offers is fantastic at the moment with cheap players, recorders and personal computers. In the audio and video tape transfer business, getting your business website to rank well in the search engines for key phrases such as ‘copy tape to cd’ or ‘convert video to dvd’ should get you a steady stream of enquiries from people who, primarily, can’t access their tapes any more. The preservation of the valuable recording is usually perceived to be CD or the DVD.
My concerns with the ‘…to CD’ and ‘…to DVD’ process are:
Optical Media that can be burnt using computers, CDr and DVDr, are not as reliable as commercially produced or ‘stamped’ discs and their quality and longevity can vary between different manufacturers.
The digital video stored on a DVD Video is a lossy compressed format that depending on the original footage and if pushed for too much running time can easily make the digital transfer look much worse than the original – not a good reason to transfer the tape!
The everyday nature of audio and video discs and some of the domestic technology we now have has conspired to make what is and can be a complex, time consuming and often problematic process too simple in the eyes of many people.
Since the early marketing of the compact disc in the ’80s by spreading jam on it to highlight its resilience compared to vinyl or tape, many of us have been taken in by this and have a skewed belief on the longevity of CD and DVD optical media. In fact optical media can degrade and become unreadable and unplayable in a very short space of time even with good storage practices. Tape based storage formats of course have their numerous problems but they can often be incredibly resilient over time even in under poor storage conditions. When tape does degrade it is rare event when it cannot be treated and made playable .
CDr and DVDr Longevity
Optical media that can be burnt form CD / DVD writers uses a dye that the laser alters to create pits that are read back as digital data. CD and DVDr discs use different dyes due to the different data storage needs. The dye can be affected by bright sunlight and compared to commercial or ‘stamped’ optical media it is not as reliable.
It has been speculated that the archival quality of CD is superior to that of DVD. The basis for this lay with the physical differences in CD and DVD optical media and the maturity of the technology. In particular, the size of the bit markings in CD media not only reduces the relative effect of media or dye degradation, but also means that more stable, less sensitive dye may be used.
Out with old, in with the new
The march of technology can cost us money while making huge profits too. This of the CD reissues of old back catalogue albums, the pressure to replace vinyl collections with CDs, video tape collections with DVDs or CRT televisions with LCD or plasma screens. New technology is marketed as ‘better’ in many ways, yet it can be worse too.
One of our audio and video archive customers has a large collection of AVCHD video files that are stored in 1.9GB ‘chunks’ as xxxxx.MTS files. All these files are of 60 minute and longer duration and must be joined, deinterlaced, re encoded to a suitable size and bitrate then uploaded for online access.
This is quite a task in computer time and file handling. These small domestic cameras produce good HD movies for a low cost but the compression to achieve this is very high and does not give you a file that is easily edited. The .MTS files are MPEG transport stream containers for H264 encoded video.
There are some proprietary solutions for MacOS X and Windows that will repackage the .MTS files into .MOV Quicktime containers that can be accessed by MacOS X or re-encoded to a less compressed format for editing with Final Cut Pro or Premiere. We didn’t need this though, just a reliable and quick open source workflow.
The first and most important issue is to rejoin the camera split files.
These cameras use FAT32 file systems which cannot handle individual files larger than 2GB so they split the .MTS video file into chunks. As each chunk in a continuous sequence references the other chunks these must be joined in the correct order. This is easily achieved with the cat command.
The rejoined .MTS files can now be reencoded to a more manageable size using open source software such as Handbrake. We also needed to deinterlace our footage as it was shot interlaced and it would be accessed on progressive displays. This will increase the encoding time but without it any movement will look odd with visible artifacts.
Finding the ‘sweet spot’ for encoding can be time consuming but in this case was important as projected text needed to be legible but the file sizes kept manageable for reasonable upload times!
We offer consultation for institutions on technical issues that arise from planning and delivering a large-scale digitisation project.
We can adapt our service according to your project's digitisation requirements, including generating and storing metadata.
At the Greatbear studio we maintain and care for one of the UK's largest collections of fully-working professional audio and video tape machines, providing the highest-possible quality transfers.
Our meticulous quality control procedures mean our clients are not burdened with less-than-optimum files buried within their collections
Greatbear frequently transfer confidential material and we guarantee the security of your tapes and their content. We regularly work under Non-Disclosure Agreements (NDAs).
Please contact us so our knowledge and experience can inform your project design.
Metadata
Metadata helps us to describe digital resources in a structured way so they can be shared with other people, organisations and between operating systems.
For archives, libraries, museums and learning institutions, creating accurate and project-specific metadata is a crucial part of establishing a successful digital preservation repository. Metadata is becoming increasingly important for those working in professional media production too.
We are able to fully support and advise organisations who need to create metadata as part of their digitisation project.
We can generate technical metadata appropriate to the source format that can become part of larger metadata schemas for digital collections.
We are able to digitise to, use and edit metadata-rich digital files such as Broadcast WAV(BWAV) and the open source MKV container widely recommended for use with the FFV1 lossless video codec.
As each project is unique and individual, we can adapt our service to correspond with the metadata framework best suited to deliver your collection.
Why digitise?
Some of the most important audiovisual heritage of the 20th and 21st centuries is stored on magnetic tape.
Often the content of collections remains inaccessible because institutions do not have the appropriate machines to play tapes back on. Older tape can also be extremely vulnerable, making it susceptible to damage in the playback process.
Digitisation helps unlock the potential of magnetic tape collections by offering the double benefits of preservation and accessibility.
There are plenty of other reasons why you should consider re-formatting your magnetic tape collections to digital files:
According to UNESCO(United Nations Educational, Scientific and Cultural Organisation),'it is estimated that we have no more than 10 to 15 years to transfer audiovisual records to digital to prevent their loss.' See also the British Library's Save our Sounds campaign, launched in 2015, which aims to raise awareness of this issue.
Key parts in many tape machines are no longer manufactured, especially in video. Many formats are now high risk as machines become difficult to service and repair. The Museum of Obsolete Media Obsolescence Ratings offer a guide to prioritising the migration or preservation of media.
Magnetic tape can easily become damaged in less-than-adequate storage conditions, leading to mould infestation or binder hydrolysis aka sticky shed syndrome.
Digital storage space in hard drives, solid state drives or in the cloud has become much larger and cheaper, making it viable for all types of collection large or small.
Bristol City Archives audio tape to be digitised
thegreatbear.co.uk has a wealth of information to aid A/V collection assessment
Museum of Obsolete Media obsolescence ratings
Adrian cleaning a Studer A80 ¼" open reel tape machine at Greatbear
Fifty Fifty Post Production
British Broadcasting Corporation (BBC) BBC Studios (Natural History Unit) Bazooka Bunny TV
Clockwork Films
Gibraltar Broadcasting Corporation IMG
October Films
Reeltime Pictures
Screen Story
Skyline Productions
STV
Sundog Pictures
Twenty Twenty Productions Untitled Film Works West Highland Animation
Williams Formula 1 Worldmark Films Yeti TV
Artists & Musicians:
Lea Anderson, choreographer
Joan Armatrading, musician Beshara, band
Blue Aeroplanes
BOB, band
Bolt Thrower, band
Bristol Archive Records, record label
Laurence Crane, composer
Deacon Blue DJ Zinc Rose English, artist Estate of Howard Hodgkin Estate of Sacha Distel
Wayne Hussey, musician
Massive Attack, band Nigel Rolfe, artist
Park Promotions, artist management
Portishead
Larry Stabbins
The Jesus Lizard
The High
The Soup Dragons The Young Gods
Therapy? Warp Records
Zenana
Cassette tapes run at a very slow speed of 17⁄8 inches per second (ips) with a very small track width of 1.59mm
Cassette decks when they left the factory or a service centre should have been aligned to a standard reference for the position of the record and play heads. Unfortunately they often weren’t all the same and over time the alignment can drift, get knocked out or manually ‘fiddled with’ by an owner.
What this means is that unless you’re playing back your tape on the machine it was originally recorded on, you may not be getting the maximum quality as the angle of the head to the recording or azimuth will not be optimal.
Without calibration tones recorded at the start of the tape (which is very unlikely on most domestic cassette tape recordings), you must set the playback azimuth manually. A few high end tape decks, namely those made by Nakamichi, either had a easily accessed Azimuth Adjust or could even automatically adjust this throughout the tape. The Nakamichi Dragon was one such tape deck and could be the best, if working well, for high quality playback.
If you want to transfer or convert a cassette to CD and adjust the azimuth yourself this is the easy way to do it:
Look at the tape path (everything the tape will move across) and if it looks brown and dirty get some isopropyl alcohol and give it a good clean with a cotton bud.
If you haven’t demagnetised your deck for a while now would be a good time to do it..
Power up your cassette deck, which hopefully works correctly and doesn’t have too much speed instability!
Pop your tape in the cassette well and start to play.
Turn your amplifier’s volume up and if you can put it in Mono.
Now, look under the tape machine’s playback or combined record and playback heads you should see a small screw or nut possibly with anti tamper paint on it.
Using an appropriate tool, turn this nut or screw a little left or right while listening to the audio.
You should hear the recording, especially if it has a lot of high frequency content such as cymbals etc. get bright and dull sounding or more technically get more in or out of phase.
Your aim is to get the most in phase or bright sounding playback.
Sounds better now?? Great, start to record using you favourite computer audio software. We like SoX for the control but there’s a huge range out there.
We often get sent Digital Audio Tapes or DATs for transfer to .WAV computer files. As these recordings are already digital or ‘born digital’ the process should be straightforward. Our audio interface cards accept the SPDIF or AES digital audio stream from the DAT machine and record this as a WAV or BWAV file. This file can then be burnt as a CD or delivered digitally on a hard drive or removable media.
The big problems though come with the tape that these digital recordings are made on. The tape is only 3.81 mm wide and moves at a very slow 8.15 mm/sec. The tape is also very thin at 13 microns. The recording system and transport used is helical scan just like in video recording but with the very slow tape speed and small tape dimensions any defects or problems with the tape can result in many errors which may not be correctable by the error-correcting system of the DAT machine.
One problem we’re starting to see more and more are tapes that snap. The tape pictured above was a D120 which was never recommended by the DAT machine manufacturers but was still often used for its extended recording time. This tape snapped without warning a quarter of the way through the recording. There were no outward signs or potential problems just a sudden clean break on a diagonal.
To recover this tape it could have been spliced with splicing tape of the correct width like in analogue recording but there is a high risk if not done perfectly of irreparable damage to heads on the drum. Even with this type of repair some of the material would have been lost. A safer solution is to rehouse each spool in another shell. This lets you recover as much as possible from the tape, without the risk of head damage.
Whichever solution you decide, the DAT shell must be disassembled. A small crosshead screwdriver needs to be used to remove all the case screws. There are two hidden ones, accessed by sliding part of the cassette shell down:
You can now carefully lift both halves of the DAT shell apart, making a note of the tape path inside the shell. Be careful not to touch the tape with your bare skin as fingermarks and grease can cause head to tape contact problems and audio errors and dropouts.
We have several of these large, wonderful machines. It’s not often we need or want to get involved in DAT machine repair as generally they are not easy to service machines and many key transport parts are becoming unavailable. The Sony 7030 DAT though has been designed with easy servicing in mind. There’s alot of room in these things and each section is clearly marked and separated into distinct boards much like Sony Broadcast video machines.
These are timecode DAT machines and were once common in video post production houses and the more well funded recording studios. The problem with some of this well built kit though is exactly that it works too well and gets left on for long periods through it’s life and this can take a toll on certain components, especially electrolytic capacitors. Heat builds up in electronic circuits, especially in switch mode power supplies that larger broadcast items often use. Capacitors have a rated life at 85°C or 105°C at several thousand hours. With hotter environments, substandard parts and long operating hours these capacitors can soon outlive their original design life.
Our 7030 DAT had started behaving oddly and at first the display would flash on and off after a short while powered on. Another machine would power up for 30 secs then just die. Before delving into the enormous service volumes it’s always worth replacing the Switch Mode Power Supplies (SMPS). These like many broadcast machines use supplies that are sometimes generic made by other companies and which can be bought at Farnell or RS. We did it the harder way and desoldered all the old capacitors in the power supply and replaced these with high quality low ESR Panasonic ones which should give us another 6000 hours of running time. So far this machine has worked perfectly although you do need good soldering and desoldering technique on these boards. A powered air desoldering station is a good idea, much, much better than a hand solder pump.
Like much late 1970s and ’80s studio recordings, this was recorded on Ampex branded tape that suffers badly from binder hydrolysis or ‘sticky shed syndrome’ that must be addressed before the tape can be successfully played and digitised. This was in addition to the mould growth that was evident on the tape pack edges, and cardboard box. Storage in damp conditions and high humidity causes this type of mould and increases the breakdown of magnetic tape generally, sometimes to the point where de-lamination occurs, that is, the binder breaks away from the polyester structure of the tape. When this happens, which is luckily quite rarely, the magnetic information is damaged and mostly lost beyond repair.
Thankfully this tape, whilst it looked in poor condition was relatively straightforward to restore but time consuming. Careful hand winding, and mould cleaning is necessary as is awareness of the potential health effects of some mould spores so good ventilation and protective masks are necessary.
We have recently worked on probably the worst looking tapes but with some of the best sounding music recordings we’ve seen for a while! A batch of 10.5″ NAB studio masters had bad tape mould growth.
Andy Leighton, owner of Bolex Brothers and music publisher of the Rocky Horror Show, found a batch of studio masters on quarter inch tape that had been growing mould for some of them over 30 years. All of these recordings had been made at the renowned Sound and Recording Mobile studios better known as SARM, later creative home of Trevor Horn.
Among these tapes was the first ever recording made at SARM in 1972 by Richard o’Brien, writer of the Rocky Horror Show, in addition to rare tracks by artists such as Kimi and Ritz.
When the tape mould was finally cleaned from the tapes and some of them baked for binder hydrolysis the quality of the recordings was very high and testament to the high quality available from analogue recording. Even though tape can be vulnerable to physical problems, it is also robust. If these had been tape-based digital recordings, in the same condition, I doubt we’d have been able to achieve the same results.
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Due the unique nature of each transfer project, we’ve found that assessing tapes prior to confirming costs is the most accurate and fair method to provide the best value services for our clients.
Audio and video tape formats vary enormously, each with multiple and varying 'issues' and potential problems to solve for the best possible transfer.
Physical degradation, age and type of tape, as well as its playback and storage history, can significantly affect the processes required for restoration and high quality digitisation.
Duration is not always possible to determine ahead of playing a tape.
We offer a range of transfer methods and digital delivery outcomes, appropriate to each project.
Every tape, job and client is different, and we'd rather find out what you want from your tapes and offer a bespoke service.
For these reasons, our audio and video tape assessment service is FREE. It's also useful if you're unsure of the physical condition, running times, track formats or general content of your recordings.
If you wish to send us your tapes for assessment, please download and print our customer tape assessment sheet to include with your package.
For many types of tape we can be flexible on price, so give us a call on 0044 (0)117 985 0500 or CONTACT US via our online email contact form. We like talking tape!
At the Greatbear studio we restore, transfer and digitise all forms of analogue and digital audio tape, including rare & legacy audio formats. Find out more about Greatbear audio transfer services here →
Our parallel specialisation is the preservation and digitisation of all broadcast, professional, domestic and 'obsolete' video formats from cassette, reel-to-reel and disc. Find out more about Greatbear video transfer services here →
For any analogue / digital, audio / video tape restoration, transfer and digitising enquiries or questions, and to download our free customer tape assessment sheet, please contact us here →
To identify your tape, analogue or digital media, please browse the formats we digitise → Here you will find easy access to pages with detailed information on every audio and video format we work with.
We love magnetic tape and the machines that play it. We're part of an international audio-visual media conservation community, and we're keen on sharing knowledge. Read the Greatbear tape blog here →
Once a common sight in Radio stations around the world, the NAB Cartridge machine or Fidelipac was used for short jingles and announcements, sometimes even for longer recordings. Using a similar sized cartridge to a domestic 8 track machine the NAB cartridge was different in that the pinch roller was not in the cartridge but would hinge up in the player and hold the tape against the capstan. Running at 7.5 inches per second (ips) compared to 3.75 ips in domestic cart machines the recording and reproduction quality good be very good but it was the ease of use and cueing ability offered by these machines that made them so useful in broadcasting.
We have Sonifex cart machines that while very well built do have rubber parts that will degrade over time and reduce the transport performance. Luckily we have some of the last remaining stock of new pinch rollers, motors and capstan drive belts.
The pinch roller in one of our machines had become quite hard and the rubber shiney over time. A pinch roller in this state may not hold the tape as securely and could also have flat spots both leading to increased wow and flutter and poor tape handling. These pinch rollers also have high quality cartridge bearings pressed into their shell. Over time these loose their lubrication, wear, become rough feeling and will also add to poor tape handling.
Older, fragile and valuable tape must be handled and used carefully. A ‘chewed’ tape caused by a poorly maintained tape transport in any tape machine, audio or video is a disaster and hard to recover from perfectly.
Both halves of the cart machine case need to be removed to easily change the pinch roller. While the access is good and the machine, in this case a Sonifex microHS, had been designed for easy servicing the pinch roller is still a little fiddly to get to so I removed the transport from the main chassis.
To remove the pinch roller a small slightly hidden C clip must be removed you can see in the image above the slot machined into the roller shaft where it sits and holds the roller. This is hard to remove as the plastic bush on top of the roller stops you getting a small screwdriver in. I managed to remove the C clip with some fine circlip pliers. Be careful not to loose the clip if you don’t have spares, they fly away very easily!
Now the new roller can be placed on the shaft. It’s a good idea once all the transport is out to give everything a good clean with IPA.
On this machine, the castan drive belt was quite slack so a new one was fitted, which is easy now the transport is removed. First though the capstan flywheel and motor pulley were cleaned of all the old rubber belt residue that tends to accumulate over time.
The last thing to do is check the pinch roller pressure. This is important to as to high or too low will increase wow and flutter, increase wear to the bearings and capstan surface and give poor tape handling. Due to the design of these NAB cart machines, the pinch pressure needs to be checked with a special cartridge. The pinch pressure is then adjusted from a screw pot on the top PCB seen outlined below in green.
Celebrate What? is a documentary we transferred and created DVD access copies for its director recently. He only had a VHS copy of the 8mm original unfortunately but it’s still a great piece of history about St Pauls, the St Pauls Carnival and Bristol.
If anyone can recognise themselves or anyone else, please contact the director, Colin Thomas by email, ctbr03509 at blueyonder.co.uk
2 U-matic video tapes were discovered of a Black Roots live performance in Bristol in the 1980s. We were able to restore, digitise and make the umatic transfer of this recording as a high quality, uncompressed Quicktime file then encode and author a DVD for future release by Bristol Archive Records.
Some information supplied by the label:
Black Roots were Bristol’s premier Reggae band throughout the eighties and having gone their separate ways in the nineties they reformed last year and will be rekindling the magic with an intimate hometown gig at the Fleece on Friday September 9th, the show coincides with the release of “Black Roots – The Reggae Singles Anthology”, released on Bristol Archive Records in collaboration with Nubian Records, this release showcases all of the band’s singles released during their first decade and as an extra bonus the CD issue comes coupled with a DVD of the band’s 1986 video release “Celebration” recorded at the long gone Studio nightclub in Bristol. This show will be something special and likely sell out so book your tickets early and don’t miss out.
We were very excited recently when Chris Bradfield from Soundscommercial uncovered a previously unseen batch of EIAJ half inch reel to reel video tapes. In the process of looking for 1976 footage for their event, Spirit of 76, we uncovered many other gems. One of these goals was the famous hat-trick scored by Kevin Mabbutt against Manchester United at Old Trafford in 1978. Mabbutt is one of only two players in Football League history even to have done this and this footage was never recorded anywhere else!
Unfortunately this large batch of valuable recordings had been stored in damp, unheated conditions and had suffered. The tape had deteriorated in several ways.
Mould growth was evident on some tapes
The oldest tapes from the early 1970s were shedding oxide severely and had little lubrication left in the binder.
Binder hydrolysis, often called sticky shed was evident on other tapes.
Each issue needed a different process to treat the tape. The common assumption that ‘tape baking‘ will restore all unplayable tape is not true. It is just one solution to one of these issues and can cause more problems if used incorrectly. Deteriorated video tape is much less forgiving than audio tape when attempting transfer and must always be handled and processed with extreme care. Crinkled, curled, edge damaged tapes are next to impossible to restore back to their original condition and it’s common that more damage can occur when owners are desperate to transfer footage.
We were able to restore all the tapes to a playable condition and make uncompressed quicktime files of these.
Below is a clip from a later recording. We are not able, unfortunately, to show the Kevin Mabbutt clip yet.
Unseen to 32 years, although there could possibly be other tapes in the vaults at Abbey Road.
This NTSC U-matic transfer to uncompressed quicktime files was a damaged tape that at some point in its life had been ‘eaten’ by a greedy U-matic machine! The tape shell also had some plastic debris inside that needed removing before it was safe to attempt loading and migration.
The capstan drive tape recorder is (or was) very common and was used in a huge range of cassette tape audio, video and open reel machines from cheap domestic to very expensive broadcast tape machines.
Occasionally we receive quarter inch tapes, always on small 3 inch spools, that reproduce on our capstan drive machines with terrible speed variation. They start off very fast then gradually slow down over the duration of the recording to around normal speed.
These reels must have been recorded on rim drive machines. These type of open reel tape recorders didn’t use a capstan and pinch roller to save space and more often cost. As there is no capstan, as the supply reel gets smaller the tape recording speed increases. When replayed on a rim drive machine the speed, while not likely to be ‘Studer stable’ will be pretty stable and the recording sound OK.
It’s not feasible or desirable for us to own unlimited machines of all types due to the time to service and repair them, find parts and storage space therefore we use a small range of carefully picked high quality tape machines that with care can replay most tapes, speeds and track formats. This is the problem with rim drive recordings and an analogue or digital solution must be found.
The tapes we received were 15 reels of family recordings from the Welsh Valleys. Others apparently had tried to transfer these tapes but gave up finding no material. This was easily solved as the tapes were wound the opposite way to normal so the oxide was facing out not in. This is the same as in audio cassettes. The original tape machine must have had its heads in a similar position to a cassette machine.
We have several time base correctors and frame synchronisers at our disposal. One recent addition is a new old stock (NOS) CEL Tetra. This is an early 1990s motion adaptive Standards Converter for PAL, SECAM, NTSC 3.58 and NTSC 4.43 systems. A very flexible unit with composite, Y/C (S-Video), U-matic DUB High Band/Low Band and component inputs and outputs.
Out unit still has its shipping caps over the BNC sockets and looks unused but after 5 minutes of power a cloud of white smoke billowed out of the cooling fan accompanied by a pungent smell. The Shaffner EMI mains filter had a nasty, sticky brown residue leaking out and all around the back of it. This is the second TBC that I’ve had this happen to. I’d assumed these units get left on for long periods when used in broadcast applications which would hasten their demise. According to their website, the mean time between failures (MTBF) of their recent products is around 2,000,000 hours! Our CEL TBC doesn’t look like it’s done more than 30 minutes so maybe there’s been some dodgy electrolytic fluid in these units just like the motherboard capacitor problems between 2000 and 2003.
We often receive enquiries about audio and video tape that is not in the best condition having been stored in humid conditions, suffering from binder hydrolysis (sticky shed) or not wound on its reel well, but we were surprised when we received this tape recently.
It literally is a bag of tape! It is a cassette tape that had at some point become unspooled, probably when the cassette shell was opened for a repair. We can and did restore the tape by respooling and reshelling before playing on one of our Nakamichi dual capstan cassette decks.
This is a time consuming job though as thin tape twists, turns and crinkles up very easily needing careful tension, customised winding systems and protection from contaminants such as dust, grease, etc that could cause more damage to an already compromised recording.
We use time base correctors and frame synchronizers all the time in the transfer and digitising of analogue video tape.
One of our more flexible and high quality units had recently developed an annoying and very obvious fault on its video outputs. While the unit was working there were faint but distinct horizontal lines on the video. This phenomenon is often called a hum bar and can be caused by ground loops.
In this case we isolated the unit from the rest of our installation and using a separate power point the problem was still there. Looking at the unit itself it is a very deep and heavy 1U case with two 40mm cooling fans at the rear corners. It is quite old too and being designed for continuous studio use is likely to get hot and have been on for very long periods.
The video fault appeared to be AC ripple ‘riding’ on the DC power. It was time to look at the electrolytic capacitors in the power supply.
Although I could have tested each one, all these caps were old and only rated for 3000 hrs at 85 celcius so they all had to go! Here’s a list of them:
The only one hard to find was the large 400v dump one. Most units now are thinner and taller but eBay came to rescue here.
This shotgun approach worked beautifully and the fault had gone. While tracing the exact fault is always the best way, capacitor often get a hard life and will not last indefinitely, especially in switch mode power supplies.
High resolution audio and video digital tape conversions can use large amounts of computer storage. 8 bit uncompressed Standard Definition (SD) PAL video runs at 70 GB per hour and 24 bit 96 kHz audio files at 2 GB per hour.
As a result of this many of our analogue to digital tape transfers require the use of external storage, usually USB 2.0 portable hard drives, to supply the copied digital transfers back to the customer. Some drives supplied by customers have not been of great quality and not designed to be sent about in the post. One such drive we had recently, a Sony Vaio branded 2.5″ USB drive wouldn’t copy certain directories of important files with the Mac OS Finder or the Windows Explorer. While most of the drive copied this certain folder always resulted in a crashed computer!
Thanks to GNU/Linux we have a bit more power and information at our disposal about hard drives and IDE or USB interfaces. It’s always best practice to copy as much information from the drive or mirror it before attempting any other types of data recovery or file system repair. Using the standard dd
One of our recent and ongoing jobs is a very large, over 2000, NAB 10.5 inch reel to reel archive of quarter inch professional tape recordings.
To fit into the budget but maintain quality we needed to find a way to streamline our workflow in converting the high resolution 24 bit 96 kHz master .wav files to CD quality (16 bit / 44.1 kHz) and MP3 (320 kbps) audio files.
Typically this would be done manually with 2 track audio software such as Audacity, Peak Audio Tools, Wavelab, etc with a Graphic User Interface (GUI). For such a large amount of individual files this is time consuming, expensive and unnecessary. While many audio editors have batch processing tools, Amadeus Pro being one of our favourites, they are still not as flexible as combining command line tools with a Bash script.
SoX is a powerful command line audio tool that can be used to edit, convert, process, record and play a wide range of digital audio files. It also has a very high quality resampling algorithm which we are using here.
Once the tape reels have been digitised they are split into individual .wav files which are then renamed with artist and track details using a php script that accesses a .csv file. These 24/96 resolution files are then converted to lower, CD resolution using SoX and to 320 kb/s MP3s using LAME. The script also uses sed, the stream editor, to add the text _16_44.wav or _mp3.mp3 to the filename for ease of identification. The script finds all files with the suffix _24_96.wav in all the subdirectories of it’s working directory and processes these.
At the moment this script is running under Mac OS X 10.5.8 using the MacPorts project but will, in time, be moved to one of our Apple G4 servers running the PowerPC version of Debian GNU/Linux 5.05 ‘Lenny’.
Using the right audio archiving equipment is essential for our work and we love older gear! We spend (possibly) more time than we should making the machines work 'as good as new,' so they deserve to be mentioned here...
3 x Sony APR 5003 with a JRF Magnetic Sciences modified head assembly for 4 track and 2 track 1/4" stereo tapes
2 x Studer A80 RC with a JRF Magnetic Sciences modified head assembly with DIN (butterfly) and NAB repro heads also drilled for easy azimuth adjustment
Studer A80 R customised for winding and cleaning of fragile tapes with no fixed heads or guides
Lindos LA101 Audio Oscillator / LA102 Audio Measuring Set
Information Terminals M-300 cassette gauge
Tentelometer tape tension gauges
Various Spring Gauges
MRL 1/4 test tapes
Teac / Nakamichi / Abex cassette test tapes
Clockwise from top left: Studer A80 RC, Fostex Model 80, Sony APR 5003s, Studer A80 RC head assembly, Fostex B16, Otari MTR-90III reel-to-reel tape recorders at Greatbear
Clockwise from top left: tape tension Tentelometers, Dolby 365 && Dolby 363 noise reduction processors, XLRs & audio patch bay wiring plan, fixing a Tascam BR20 circuit board, patchbay terminals, Information Terminals M-300, cassette tape transport alignment gauge
Clockwise from top left: Sony PCM 7040, Sony PCM 7030, studio monitors, Fostex D5 DAT, Alesis ADAT LX20, Alesis ADAT XT, Tascam DA-45HR, Tascam DA-60 MKII, Tascam DA-98HR, MOTU digital timepiece, Sony SL-T50ME, Sony SL-700ME, Sony PCM-701ES
The above image is an extreme example of a binder problem with 1/4 inch tape leading to delamination where the oxide is literally peeling away from the tape. Once this has happened there’s no going back. So much of the binder had peeled away that the tape, while parts of it finally playable, had very obvious dropouts affecting both channels. Sticky Shed Syndrome is the common name for binder hydrolysis which is common, especially in Ampex branded tape made from the 1970s through the late 1980s but it can be seen in other brands and types of audio and video tape too. Tape baking is one common approach to temporarily resolving this problem and if used carefully in an low temperature incubator, not a domestic oven, it is a safe and repeatable process for valuable tapes.
Don’t worry, we won’t let this happen to your tapes!
Certain brands and batches of magnetic tape can and often do have similar problems but rarely as extreme. With experience we know what to look out for and have the right tools to treat such tapes correctly so they can be restored, replayed and transferred.
We have a Thermo Scientific Heraeus B20 laboratory incubator that can hold low temperatures very accurately over long periods while also having a safety upper temperature cutout to protect against over heating. Not something you want to do with magnetic tape! With tools such as this, our Studer A80s and our Sony APR 5003 tape machines, we are able to gently handle and digitally migrate at high bitrates all track formats and speeds of quarter inch analogue audio tape.
Cleaning Tape
Some tapes which may not have ‘Sticky Shed Syndrome’ may have other binder problems and need manual cleaning too. This, if done appropriately, is a safe process and helps to reduce the loose binder clogging the heads and so creates a better sounding transfer.
Winding Tape
Being able to bake tapes at a stable temperature is one part of the process but careful winding of the tape is important. While some tapes are so degraded that they cannot risk being wound at all, many tapes exhibit ‘pack slip’ and need this addressed before it’s safe to bake.
Many audio and video tape transports can be rough with tape, having several fixed guides that the tape rubs over, and harsh or incorrectly adjusted reel brakes that can stretch tape or very high tape tension that can risk delaminating older fragile tapes.
We have a modified Studer A80 RC which handles tape very gently, having no fixed guides for the tape rubs against.
Sticky Shed Syndrome in Video Tape
It’s not just audio tape that can degrade!
Video tape can exhibit the same issues in deterioration as audio tape and can be even more of a problem, due to the tape path and scanning video heads, in the transfer process. We are able to restore, clean and bake video tape too, when necessary.
We have two of these excellent machines in addition to our Sony APR 5003s and Studer A80s. The Tascam BR-20 was Tascam’s last and top of the range 1/4 inch reel to reel tape machine and available in two track stereo and stereo with centre timecode option.
The capstan drive in the BR20 is belt driven by a wide belt. Both belts in our machines looked OK but we’ve replaced all roller bearings, belts and pinch rollers in both of our machines anyway as a matter of course. These parts are still available from Teac UK via Acoustic Services on 01-844-347600.
Below is a simple explanation of how to change the capstan belt.
Unplug machine from mains power and move to a strong stable base.
Remove cross head screws from the rear panel and lift plate off. Depending on the type of plug in your country you may not be able to remove it completely.
You’ll now be able to see the capstan motor and it’s control board attached to it.
Remove the 4 cross head screws and gently lift the analogue audio output board away from the machine as in the picture above.
We now need to remove the whole capstan motor assembly with the control board still attached. Remove the 4 cross head screws right at the front of the assembly, NOT the six nearest to you when looking at this image.
Carefully unclip the 4 cable connectors from the motor control board. The other connector cannot be removed from the board and must be removed where it connects to the other board.
The whole assembly can now be lifted out from the machine. Be careful to not snag any cables and remember to unclip the black cable ties.
You’ll now be able to unclip the control board from the assembly by carefully compressing the black clips with some needle nose pliers.
Now remove the six cross head screws holding the capstan motor assembly together. This is the only way to remove and refit the capstan belt. There’s not enough room to do it any other way!
Now you can remove the old belt and capstan shaft. It’s a good idea to clean the capstan with IPA where the old belt has run and reapply a little grease to the bearing end of the capstan.
Fit your new belt and reassembly is the reverse of dissasembly! Be careful though to not drop the screws into regions you can’t get them out of – luckily there aren’t that many on this machine but a long magnetic screwdriver is very useful.. just don’t get it anywhere near the headblock and heads!
This is something you don’t see everyday! An almost unused and boxed 1/4″ 2 track reel to reel tape machine, a Tascam BR20 one of their highest quality machines sometimes installed with a Timecode head for broadcast and editing applications.
This machine somehow turned up at an IT Recycling centre in Essex but is now in much safer hands transferring tapes, in particular a very large archive of library music on 10.5″ NAB reels owned by Mood Media Ltd.
As you can see this machine is in its original box, with packaging and first look at the heads show almost no head wear but some nasty oxide that took a while to clean off.
This machine needed little work to bring it back to spec, a new capstan belt, pinch roller, tape tension and speed setting and a full calibration.
The capstan belt change is the subject of another blog post here..
