audio technology, machines, equipment

Reel-to-reel, cassette and cartridge tape machines, equipment and digitisation technology used in the Greatbear audio tape transfer studio

Museum of Magnetic Sound Recording – interview with Martin Theophilus

How did the Museum of Magnetic Sound Recording get started, what kind of equipment does it collect and what do they think the future holds for magnetic tape?

Many thanks to Martin for taking time to respond to our questions. If you want to support the Museum of Magnetic Sound Recording’s aim to establish a permanent storage facility you can make a donation here.

Enjoy!

GB: When and how did the Museum of Magnetic Sound Recording get started?

M: The Museum was created in an effort to preserve our vintage recording collection that was initiated in 1998 with the web site Reel2ReelTexas.com. My audio recording began professionally in 1964. Our production switched to video in the early 1990’s. In 1998, the collection began with a gift of an Edison cylinder player from my wife Chris. I missed having the tape recorders around, so we began acquiring the recorders I’d worked with and then several historically significant recorders were secured. One included the first professional magnetic tape recorder built in the US. It is the 1948 Ampex 200A #33 reel to reel tape recorder belonging to Capitol Records. We also have Willie first T-26 Dynavox tape recorder

We have many very first recording devices from: Ampex, Berlant, Brush, Magnecord, Pioneer, Sony, Studer and Teac/Tascam. While there are not many large multi-track recorders, the intent was to display those recording devices that assisted musicians in creating their music. There are now around 225 tape recorders and 100 + vintage classic microphones. in 2012 we decided the collection was of significance and needed to be preserved and made available to the public in a permanent secure facility. We founded the non-profit and acquired a dedicated Board with all original members staying the course with us.

GB: How are you funded and how can people view the collection?

M: Presently the Museum is funded by private donations. At this time we are functioning with volunteers and the collection is available to view on line. By appointment we provide private tours in our Studio/Museum.

GB: What is your favourite piece of (working) equipment and why?

That’s difficult, however it is the Studer A807. It is in excellent condition and is one of the top Studer machines produced. Incidentally they had a wonderful museum saving their history. It disappeared after Harmon took Studer over.


A tour of the Studer tape recorder and mixer ‘museum’ and a company history, recorded in Switzerland before the museum relocated to the Soundcraft Studer HQ in the UK.

GB:What is your favourite piece of (non-working) equipment and why?

M: There has to be two. 1) One would be the Ampex 200A #33 mentioned above. It just needs motor capacitors and will be operating soon. The 200A was overbuilt and weighed 240 lbs. While it originally belonged to Capitol Records, it eventually ended up with the San Francisco engineer/producer Leo De Gar Kulka.  2) The second is the Sony TC-772 half track 15 ips portable location recorder. It too needs motor capacitors. It was able to complete long high quality remote recordings and provided audio limiters, vari-speed and XLR connections. Beautiful design.

GB: What are the challenges of preserving magnetic sound recording? Is there a tension between keeping the machines working, and preserving their appearance as museum exhibits? Do you also seek to preserve the context surrounding the machines, i.e., marketing materials and so forth?

M: We strive to acquire the most complete and working examples of the items in the collection. Several, including another favourite – the Technics RS-1700, was traded up six times before we acquired a showroom quality recorder. The same was true for its dust cover and now both are “as new.” The working units need to be exercised regularly, oiled, heads cleaned and aligned and kept as clean as possible. I can go around the collection one day and everything is working well. The next day there may be a tour and some will always be finicky. The Swiffer duster is a valuable tool to keep the items clean. They are all in air conditioned rooms, but it is Texas and there will be dust.

The things we believe set our collection apart from others are: 1) most units work, are connected to sound systems and can be demonstrated, and 2) for each unit we have acquired and display not only manuals, but also ads, brochures, reviews and posters. All of these are scanned loaded to the web site.

Currently, we have over 1,000 images that are waiting to be processed and added to the site. Additionally, the Museum has most of the radio catalogs (Allied, Burstein Applebee, Lafayette, Olsen, Radio Shack, and more) and magazines (AES Journals, Engineer Producer, Db, Modern Recording, Tape Recorder, etc.) that advertised tape recorders from the 1930’s until they quit publishing. The recorder and microphone sections have also been scanned and added to the website.

GB: What kind of people come to the museum tours? What response do they have the material?

M: Most of the tours we provide are: folks who have been active in the recording industry; professional musicians; other collectors; radio and TV related folks; persons who have viewed the web site and are visiting in the Austin area; students; teachers; and people who are making a donation of a piece of equipment.

The responses have been overwhelming. As are visits to the web site.  We maintain an ongoing web site survey asking if folks support the creation of our permanent public facility.

GB:Do you ever work with audio visual archivists to offer advice about preservation?

M: In the Spring of 2015, University of Texas at Austin’s School of Architecture’s Third Year Interior Design Class completed 11 interior designs for our Museum. One of the students won a $30,000 scholarship with her museum design. In that process, the UT School of Architecture provided significant information regarding preservation practices. The Bob Bullock Texas State History Museum’s Deputy Director, Margaret Koch, has been a supporter and mentor for our museum and provided many recommendations for preservation as we move forward. Just in the past couple of weeks, Peter Hammer, curator of the Ampex Museum prior to its donation to Stanford University, has agreed to provide our museum with preservation practices. Peter also envisions our re-creating the original Ampex Museum within our Museum of Magnetic Sound Recording. While we maintain the collection in a climate controlled studio, we will be more able to adhere to preservation practices when we have a permanent public facility.

GB:What do you see as the future of magnetic sound recording?

M: Magnetic sound recording will hopefully always be preserved and new discoveries integrated into the current knowledge. Magnetic cassettes have recently gained new attention (vinyl too). Maybe reel tape recorders will make a comeback. On our home page we show a new Revox A77 reel tape recorder being built by Akai. Otari still custom produces their classic MX-5050 reel tape recorder.

More importantly, professional recording studios around the globe are finding that many musicians love analogue recordings, so they are retaining, or acquiring analogue recorders. The evolutionary period of magnetic recording beginning in Germany in 1934 to the dawn of digital around 1982, spans an almost fifty year period. While the recording quality of vinyl had evolved and many still consider it of top reproduction quality, the advent of magnetic tape with the ability to edit and reproduce multiple copies was an incredible breakthrough.

GB:Your website is full of amazing information. What is the relationship between the online site and the physical museum?

M: Interesting question, because our intent has always been to provide as much web information as possible (far beyond the physical collection). In our recent conversations with Peter Hammer, the Ampex Museum curator, it is his belief that our preservation work: saving and scanning manuals, ads, catalogs, letters and all the supporting documentation, will actually be more significant than the actual machines themselves. 

Peter states “When I say to people,“Digits last longer than molecules”, that tends to make them think twice about the extreme impermanence of physical collections, especially after I tell them horror stories like the Ampex Museum, the Anna Amalia Library fire in Weimar in 2004, the Cologne City Museum collapse in 2009, and now a new one for me, the sad demise of the Studer collection. Physical collections simply cannot withstand the vagaries of governmental agencies, corporations, private owners, the weather, or seismic stability!”

However, I am still passionate about creating a safe permanent public facility for the collection. There is much to be said for folks being able to actually view and operate a vintage recorder and view the process of making a recording.

GB: Anything else you want to say?

M: We have come to realize that to implement our vision, we will require a major donor who would enable the museum in the long term. We also found that preserving recording technology cannot compete with the museums that are preserving the musicians and their music. The Bob Bullock Texas History Museum considered displaying some of our magnetic recording items when they expanded their Texas music section. However they determined that folks were more likely to visit displays about Texas music. For that reason they went with the history of the Austin City Limits and items from music collections from the Rock ’n Roll Hall of Fame and the Grammy Museum.
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In closing, I thank you for this opportunity you’ve given me to reflect on what our goals are. We have responded to many promising opportunities, received significant verbal support, but have yet to bring the permanent facility to fruition. Due to last year’s heavy production schedule and some folks who did not follow through, I was discouraged. So last October I told our Board that maybe the museum had run its course. However, they would have none of that and encouraged us to push forward. Shortly after that we received a nice donation and I met Peter Hammer who has become an excellent resource who will be providing valuable Ampex documents and preservation consultation. So I feel very positive about our mission and will be happy to keep you posted as we progress.

Posted by debra in audio tape, audio technology, machines, equipment, 0 comments

Guest post: Refurbishment of Magnetic Recording Heads – Terry Summers

Below is a guest post written by Terry Summers from Summertone Ltd. We first encountered Terry because of his expertise refurbishing analogue magnetic tape heads.

As one of the few, if not only, specialist UK-based company working in this area, we wanted to know more about Terry’s work. We were keen to understand the secrets of magnetic tape refurbishment, and whether Terry accepted that obsolescence for analogue media was imminent, as many audiovisual archivists claim. Many thanks Terry for taking the time to write the article, we hope you enjoy it.

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a gap inspection being carried out on an Ampex, half inch, two track, stereo replay head.

a gap inspection being carried out on an Ampex, half inch, two track, stereo replay head

Before I opened Summertone Ltd. I was for very many years, the Managing Director and magnetic head designer for the head manufacturing company Branch & Appleby. This was a specialist company serving the audio recording industry with magnetic heads as a supplier to Original Equipment Manufacturers in the analogue tape and film industry and for replacement heads for other types. B & A was particularly strong in the magnetic head supply for recording on perforated film for the synchronisation and editing of film sound, being the supplier of heads to many OEM studio film equipment manufacturers. The range of analogue heads designed and made by B & A was legion, ranging from 32 track 2 inch to 8mm film heads. B & A also supplied heads for other purposes, magnetic card readers and bank note verifiers being examples.

To be able to refurbish a magnetic head, it is essential to understand the working, the manufacturing principals and the materials used in it’s manufacture.

That expertise is with Summertone and is the reason for its success. The various magnetic materials used (mumetals of various grades, vitrovacs, ferrites etc.) each require specialist equipment and methods of surface finish to obtain intimate contact with the recording medium. A fact that is frequently overlooked is that a refurbished magnetic head has a performance that is superior to when it was new! The reason is that the magnetic losses due to the gap depth are less. So refurbishment not only restores the head’s ability to contact the magnetic material correctly, having removed the uneven wear caused by the abrasive recording medium, but also gives the head an improved performance, essential for the reproduction of archive, sometimes damaged material.

Digital Changes

The audio industry has of course changed with the coming of the digital age, some say for the better, but others disagree. We refurbish analogue heads for studios and individuals that are dedicated to the recording and reproduction of sound with the full complement of all the harmonics that are lost with a digital frequency cut off. We cannot hear them, but they colour the overall sound picture that we hear. That is the reason for the continuation of the use and restoration of the abundance of analogue machines by our studio customers (and some private users also).

The magnetic head is the vital link with the medium and is essential that it is kept in tip-top condition.

There are also many archival organisations that require the services of head specialists. The British Film Institute for instance, prides itself with the fact that the preserved sound it achieves is in many cases superior to the original public performances. This is due to their keeping their magnetic/optical sound pickups in excellent order and then, after transfer, using modern digital techniques to manipulate and store the results. Summertone receives heads from all over the world for refurbishment and is proud and pleased to say that the percentage of heads that it receives for refurbishment that are not able to receive suitable treatment, is very small indeed.

The scarcity of machines can be a problem, but as the number of studios using analogue machines diminishes they tend to pass to dedicated companies and individuals who appreciate their importance and who go to great lengths to ensure they are kept in a working condition or used for spares, not thrown in the skip. We appreciate that this cannot go on for ever, but the indications at the present time are that there are many who have the expertise to help in the specialist areas needed to keep archive machines in good working order.

It is a fact that the older analogue machines seem to be so well designed and built that they have very few faults that cannot be rectified easily. For instance, last week we switched on a 1960s valve recorder that had not been run for very many years. It performed perfectly. Another just needed a simple capacitor replacement for it to also perform. The point we are making is that the older technology was, and still is, reliable and understandable, unlike many modern machines.

It is possible to build new tape head blocks from scratch, but that is really not economical due to cost. We can, and do, still have replacement heads made to my designs but only if it is justified to keep a valuable, scarce, rare format, machines functioning. There are heads around, both new and second hand that can be refurbished. These can be obtained by combining two machines both for mechanical parts and heads. Summertone also has a small stock of heads.

Obsolescence

I do not agree with the archivists who say that there is a 10-15 year span left to transfer material. Magnetic tape and film has stood the test of longevity without deterioration which is why it is still being used for digital archiving. More modern archive methods have been failing. With good maintenance, analogue machines have a good life left and spares are still able to be obtained and manufactured as they are understandable to good engineers. I am sorry to say that when Summertone closes, our expertise for magnetic heads will be lost as it has not been possible to transfer a lifetime of analogue experience to another, due partly to the lack of financial incentive.

Posted by debra in audio tape, audio technology, machines, equipment, 2 comments

ADAT digital multi-track recorders

The Alesis ADAT digital multi-track tape recorder is an iconic piece of early 1990s audio recording equipment.

ADATs used consumer S-VHS video tape to record up to 8 tracks of digital audio.

They were modular, meaning that each machine could be synched with up to 15 other ADAADAT type II machineT machines. It was therefore possible, in theory, to create a home recording studio with capacity to simultaneously record 128 tracks of audio, a process known as ‘mega-tracking’.

Similar to other early digital audio technology such as PCM 7030 and DAT, ADAT utilised recording methods originally developed for analogue video tape.

In analogue video the use of helical scanning and rotating recording/ playback heads was the means to produce the larger bandwidth necessary to capture the analogue video signal.

Helical scanning was logically re-purposed for recording digital audio because it similarly requires substantial bandwidth (the original ADAT recorded at a sampling rate of 48 kHz/ 16 bits).

Recording revolution

According to George Petersen ‘the Alesis ADAT changed the entire recording industry, beginning a revolution of affordable recording tools. Overnight, the cost of digital studio recording plummeted from a sizeable $150,000 for the Sony PCM-3324 24-track to a relatively modest $12,000 for three ADATs at their original $3,995.’

Figures from the Audio Engineering Society suggest that ‘20,000 were sold in its first year from October 1992 to November 1993 and 80,000 sold by 1998.’

Sound studies scholar Jonathan Sterne argues that ‘ADATs were symbolic of the democratization of audio recordings and changes in the audio industry,’ facilitating ‘the rise of amateur recording and a whole “semi-professional” realm of small studios, often located in homes or other less-than-optimal acoustic spaces.’

ADAT at Greatbear

At Greatbear we receive relatively few ADAT recordings in comparison with analogue multi-track formats.

This may be because ADAT is ‘recently obsolescent,’ and for everyday reasons users of this technology have not got around to migrating their archive to digital files.

Like all early digital audio formats recorded on tape, however, ADAT raise specific preservation concerns.

As we have stressed before, tape-based digital recordings do not degrade gracefully. They are subject to catastrophic rather than moderate signal loss. If the original recording has errors that prevent the ‘smooth’ playback of the tape (e.g., from clogged heads or the presence of dust), or there is any kind of damage to the tape surface (scratches or mould), this will create irreversible drop outs within the preservation copy.

As an emergent format used by people with a range of technical expertise, it seems reasonable to expect ADAT recording practices to be a little unsettled and experimental. The physical strain on both tape and transport in a heavy production environment must also be considered (the shuttling back and forth of the tape mechanism), as this would have shaped the quality of the original recording.

In the Greatbear studio we have several ADAT machines (the Alesis M20, ADAT XT and ADAT LX20) ready to transfer your tapes.

We deliver transferred files as individual, synchronised track ‘stems’ and use ADAT ‘sync’ and optical cables to ensure an authentic born digital workflow.

Perhaps now is the time to remix that early digital multi-track masterpiece…

Posted by debra in audio tape, audio technology, machines, equipment, 0 comments

New additions in the Greatbear Studio – BBC-adapted Studer Open reel tape machine

BBC Adapted Studer_FaderWe recently acquired a new Studer open reel tape machine to add to our extensive collection of playback equipment.

This Studer is, however, different from the rest, because it originally belonged to BBC Bristol. It therefore bears the hall marks of a machine specifically adapted for broadcast use.

The tell tale signs can be found in customised features, such as control faders and switches. These enabled sound levels to be controlled remotely or manually.

 The presence of peak programme meters (P.P.M.), buttons that made it easy to see recording speeds (7.5/ 15 inches per second), as well as switches between cues and channels, were also specific to broadcast use.

Adapted Studer_Sound Levels

Studer tape machines were favoured in professional contexts because of their ‘sturdy tape transport mechanism with integrated logic control, electronically controlled tape tension even during fast wind and braking phases, electronic sensing of tape motion and direction, electronic tape timing, electronic speed control, plug-in amplifier modules with separately plug-gable equalization and level pre-sets plus electronic equalization changeover.’

Because of Studer’s emphasis on engineering quality, machines could be adapted according to the specific needs of a recording or broadcast project.  

In our digitisation work at Great Bear, we have also adapted a Studer machine to clean damaged or shedding tapes prior to transfer. The flexibility of machine enables us to remove fixed guides so vulnerable tape can move safely through the transport. This preservation-based adaption is testimony to the considered design of Studer open reel tape machines, even though it diverges from its intended use.    

If you want to learn a bit more about the Equipment department at the BBC who would have been responsible for adapting machines, follow this link.

Adapted Studer_BBC Bristol

ADAPT, who are researching the history of television production also have an excellent links section of their website, including one to the BBC’s Research and Develop (R&D) archive which houses many key digitised publications relating to the adoption and use of magnetic tape in the broadcast industry.

Posted by debra in audio tape, audio technology, machines, equipment, 0 comments

Future tape archaeology: speculations on the emulation of analogue environments

At the recent Keeping Tracks symposium held at the British Library, AV scoping analyst Adam Tovell stated that

‘there is consensus internationally that we as archivists have a 10-20 year window of opportunity in which to migrate the content of our physical sound collections to stable digital files. After the end of this 10-20 year window, general consensus is that the risks faced by physical media mean that migration will either become impossible or partial or just too expensive.’

This point of view certainly corresponds to our experience at Greatbear. As collectors of a range of domestic and professional video and audio tape playback machines, we are aware of the particular problems posed by machine obsolescence. Replacement parts can be hard to come by, and the engineering expertise needed to fix machines is becoming esoteric wisdom. Tape degradation is of course a problem too. These combined factors influence the shortened horizon of magnetic tape-based media.

All may not be lost, however, if we are take heart from a recent article which reported the development of an exciting technology that will enable memory institutions to recover recordings made over 125 years ago on mouldy wax cylinders or acid-leaching lacquer discs.

IRENE (Image, Reconstruct, Erase Noise, Etc.), developed by physicist Carl Haber at the Lawrence Berkeley National Laboratory, is a software programme that ‘photographs the grooves in fragile or decayed recordings, stitches the “sounds” together with software into an unblemished image file, and reconstructs the “untouchable” recording by converting the images into an audio file.’

The programme was developed by Haber after he heard a radio show discuss the Library of Congress’ audio collections that were so fragile they risked destruction if played back. Haber speculated that the insights gained from a project he was working on could be used to recover these audio recordings. ‘“We were measuring silicon, why couldn’t we measure the surface of a record? The grooves at every point and amplitude on a cylinder or disc could be mapped with our digital imaging suite, then converted to sound.”’

For those involved in the development of IRENE, there was a strong emphasis on the benefits of patience and placing trust in the inevitable restorative power of technology. ‘It’s ironic that as we put more time between us and the history we are exploring, technology allows us to learn more than if we had acted earlier.’

Can such a hands-off approach be applied to magnetic tape based media? Is the 10-20 year window of opportunity described by Tovell above unnecessarily short? After all, it is still possible to playback wax cylinder recordings from the early 20th century which seem to survive well over long periods of time, and magnetic tape is far more durable than is commonly perceived.

In a fascinating audio recording made for the Pitt Rivers Museum in Oxford, Nigel Bewley from the British Library describes how he migrated wax cylinder recordings that were made by Evans Pritchard in 1928-1930 and Diamond Jenness in 1911-1912. Although Bewley reveals his frustration in the preparation process, he reveals that once he had established the size of stylus and rotational speed of the cylinder player, the transfer was relatively straightforward.

You will note that in contrast with the recovery work made possible by IRENE, the cylinder transfer was made using an appropriate playback mechanism, examples of which can accessed on this amazing section of the British Library’s website (here you can also browse through images and information about disc cutters, magnetic recorders, radios, record players, CD players and accessories such as needle tins and headphones – a bit of a treasure trove for those inclined toward media archaeology).

Perhaps the development of the IRENE technology will mean that it will no longer be necessary to use such ‘authentic’ playback mechanisms to recover information stored on obsolete media. This brings us neatly to the question of emulation.

Emulation

Insides of a beta-hi-fi machine

If we assume that all the machines that play back magnetic tape become irrevocably obsolete in 10-20 years, what other potential extraction methods may be available? Is it possible that emulation techniques, commonly used in the preservation of born-digital environments, can be applied to recover the recorded information stored on magnetic tape?

In a recent interview Dirk Von Suchodoletz explains that:

‘Emulation is a concept in digital preservation to keep things, especially hardware architectures, as they were. As the hardware itself might not be preservable as a physical entity it could be very well preserved in its software reproduction. […] For memory institutions old digital artifacts become more easy to handle. They can be viewed, rendered and interacted-with in their original environments and do not need to be adapted to our modern ones, saving the risk of modifying some of the artifact’s significant properties in an unwanted way. Instead of trying to mass-migrate every object in the institution’s holdings, objects are to be handled on access request only, significantly shifting the preservation efforts.’

For the sake of speculation, let us imagine we are future archaeologists and consider some of the issues that may arise when seeking to emulate the operating environments of analogue-based tape media.

To begin with, without a working transport mechanism which facilitates the transmission of information, the emulation of analogue environments will need to establish a circuitry that can process the Radio Frequency (RF) signals recorded on magnetic tape. As Jonathan Sterne reflects, ‘if […] we say we have to preserve all aspects of the platform in order to get at the historicity of the media practice, that means archival practice will have to have a whole new engineering dimension to it.’

Yet with the emulation of analogue environments, engineering may have to be a practical consideration rather than an archival one. For example, some kind of transport mechanism would presumably have to be emulated through which the tape could be passed through. It would be tricky to lay the tape out flat and take samples of information from its surface, as IRENE’s software does to grooved media, because of the sheer length of tape when it unwound. Without an emulated transport mechanism, recovery would be time consuming and therefore costly, a point that Tovell intimates at the beginning of the article. Furthermore, added time and costs would necessitate even more complex selection and appraisal decisions on behalf of archivists managing in-operative magnetic tape-based collections. Questions about value will become fraught and most probably politically loaded. With an emulated transport mechanism, issues such as tape vulnerability and head clogs, which of course impact on current migration practices, would come into play.

Audio and video differences

On a technical level emulation may be vastly more achievable for audio where the signal is recorded using a longitudinal method and plays back via a relatively simple process. Audio tape is also far less propriety than video tape. On the SONY APR-5003V machine we use in the Greatbear Studio for example, it is possible to play back tapes of different sizes, speeds, brands, and track formations via adjustments of the playback heads. Such versatility would of course need to be replicated in any emulation environment.

helical scanThe technical circuitry for playing back video tape, however, poses significantly more problems. Alongside the helical scan methods, which records images diagonally across the video tape in order to prevent the appearance of visible joints between the signal segments, there are several heads used to read the components of the video signal: the image (video), audio and control (synch) track.

Unlike audio, video tape circuitry is more propriety and therefore far less inter-operable. You can’t play a VHS tape on a U-Matic machine, for example. Numerous mechanical infrastructures would therefore need to be devised which correspond with the relevant operating environments – one size fits all would (presumably) not be possible.

A generic emulated analogue video tape circuit may be created, but this would only capture part of the recorded signal (which, as we have explored elsewhere on the blog, may be all we can hope for in the transmission process). If such systems are to be developed it is surely imperative that action is taken now while hardware is operative and living knowledge can be drawn upon in order to construct emulated environments in the most accurate form possible.

While hope may rest in technology’s infinite capacity to take care of itself in the end, excavating information stored on magnetic tape presents far more significant challenges when compared with recordings on grooved media. There is far more to tape’s analogue (and digital) circuit than a needle oscillating against a grooved inscription on wax, lacquer or vinyl.

The latter part of this article has of course been purely speculative. It would be fascinating to learn about projects attempting to emulate the analogue environment in software – please let us know if you are involved in anything in the comments below.

Posted by debra in audio tape, audio technology, machines, equipment, video tape, video technology, machines, equipment, 0 comments

Repair Teac A3440 4 track Multitrack Reel to Reel

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.

teac-a3440 sticky broken capstan belt

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:-

  1. Remove both screws holding the capstan flywheel against the front panel.
  2. Make sure the flywheel is cleaned of all old belt debris.
  3. Make sure the motor wheel is cleaned of all old belt debris.
  4. Refit new belt over small motor wheel, then flywheel.
  5. 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

teac a-3440 capstan motor micro switch

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:

  1. Unscrew and move away the control PCB to get more space
  2. Make a note of or photograph wiring connections for switches.
  3. Unscrew and carefully desolder the existing microswitches.
  4. 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!

See our next post for the repair of this problem…

Posted by greatbear in audio tape, audio technology, machines, equipment, 6 comments

8 track cassette capstan motor tascam 238 syncaset

We specialise in tape transfers, many of which are multitrack cassette tapes.

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 better parts situation than other 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…

For 4 track and 8 track multitrack cassette transfer, see our dedicated page, and please contact us for more information.

 

 

Posted by greatbear in audio tape, audio technology, machines, equipment, 8 comments

azimuth adjustment when you transfer and convert cassettes to cd

Cassette tapes run at a very slow speed of 178 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 get drift, get knocked out or manual ‘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 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:

  1. 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.
  2. If you haven’t demagnetised your deck for a while now would be a good time to do it..
  3. Power up your cassette deck, which hopefully works correctly and doesn’t have too much speed instability!
  4. Pop your tape in the cassette well and start to play.
  5. Turn your amplifier’s volume up and if you can put it in Mono.
  6. 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.
  7. Using an appropriate tool, turn this nut or screw a little left or right while listening to the audio.
  8. 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.
  9. Your aim is to get the most in phase or bright sounding playback.
  10. 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.

 

Posted by greatbear in audio tape, audio technology, machines, equipment, 1 comment

Sony PCM 7030 DAT repair

Sony PCM 7030 DAT machine

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.

Posted by greatbear in audio tape, audio technology, machines, equipment, 4 comments

Replace pinch roller on Sonifex NAB Cartridge machine

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.

Sonifex NAB cart pinch rollers

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.

Sonifex NAB cart machine microhs transport removed

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.

Sonifex microHS new pinch roller

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.

Sonifex NAB cart machine capstan flywheel

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.

NAB cartridge pinch pressure adjustment

That’s it, time to play carts again.

Posted by greatbear in audio tape, audio technology, machines, equipment, 8 comments

reel to reel tape transfer of rim drive or capstan free recordings

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.

Posted by greatbear in audio tape, audio technology, machines, equipment, 1 comment

Replace Tascam BR 20 Capstan Belt

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.

Tascam / Teac BR 20 rear panel removed

  1. Unplug machine from mains power and move to a strong stable base.
  2. 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.
  3. You’ll now be able to see the capstan motor and it’s control board attached to it.
  4. Remove the 4 cross head screws and gently lift the analogue audio output board away from the machine as in the picture above.
  5. 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. 
  6. 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.Tascam BR 20 capstan motor board with cables removed
  7. 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.
  8. You’ll now be able to unclip the control board from the assembly by carefully compressing the black clips with some needle nose pliers.
    Tascam BR 20 capstan motor board unclipped from assembly
  9. 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!
  10. 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.
  11. 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!
    New Teac capstan belt for Tascam BR20 reel to reel tape machine
Posted by greatbear in audio tape, audio technology, machines, equipment, 2 comments

Tascam BR 20 reel to reel new in box (not for sale)

Tascam Br 20 reel to reel tape machine box

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..

Tascam BR 20 reel to reel tape recorder

Posted by greatbear in audio tape, audio technology, machines, equipment, 12 comments

Tascam 234 4 track cassette capstan belt replacement

I’ve had these belts sitting around for a few months now and they’ve finally come around on my to do list. Thinking this would be nice and easy like the Teac C-3x belts I whipped the cover off my 234 eager to put it back to work transferring those thousands of undiscovered bedroom gems that must be around in peoples’ cupboards.

Tascam 234 4 track tape transport

Tascam 234 4 track tape transport

Looked nicely laid out and well constructed as all this old Tascam equipment seems to be. I thought I’d just take the transport out and it’d be easy. There are just two belts in the 234, the capstan belt and the belt that moves the transport up and down. This cam mode belt had stretched and come off and the capstan belt had pretty much disintegrated. Once I start I find it hard to stop and this isn’t a quick job the first time, you need to be methodical and patient, good screwdrivers help too.

Well here comes the process, it seems pretty daunting at first when you see how many boards, cables and bits you have to remove and disassemble to replace the belts.

Continue reading →

Posted by greatbear in audio tape, audio technology, machines, equipment, 25 comments

Teac C-3x capstan belt

I recently ordered and replaced the capstan and counter belt on this cassette deck. These parts are easily available from Fred Marrs who sells a huge range of correctly sized replacement belts through his eBay shop. He has even gone to the lengths of remanufacturing the Nakamichi OC 8096 capstan belt to the correct specs.

This Teac machine is a really nice 3 head cassette deck, built like a tank, and very similar if not identical to the original Tascam 122. I don’t use this deck for normal cassette transfers as I feel my Nakamichi decks generally sound better but this is one of the few decks that can record and playback at double the normal speed so it’s reserved for these transfers and as a backup.

The transport is quick and easy to remove and the belt was easy once the capstan had been removed – this was also greased and oiled a little too.

Teac C-3x transport removed

Teac C-3x transport removed

Teac C-3x capstan motor with new belt

Everything went well until  I tested it with an old tape – It would play for a few seconds then the take up reel would stop letting tape get pulled around the pinch wheel, well and truly chewed!  It looked like the rubber drive wheel that the reel motor works against has perished at one point or slips. I also noticed that the little rubber sleeves that act as brakes on the reels have perished too. I’m going to have to get it all apart again to fix this – see below for more soon..

Oh and here’s a the service manual for free, so you don’t have to get fleeced by an eBay seller who’s downloaded a load of free manuals.

Teac C-3x Service Manual

Posted by greatbear in audio tape, audio technology, machines, equipment, 13 comments