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About dela

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    I have been working with film post production for 12 years; I am now primarily working with TV (on a danish national broadcaster, as well as being involved i film projects. I am quite fascinated by Nagra recorders and everything connected with them.

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  1. I couldn´t resist checking eBay, and I found it; the seller is certainly not underselling it... To call it a high quality swiss broadcast quality mixer is a bit of a stretch. It might be custom made for radio work, but it seems like an inhouse job at a broadcaster, and not really a particularly good one. The component quality is mostly OK, but the switches and potentiometers are mediocre, and not even as new would they be very good. By now they are probably corroded and need to be replaced, luckily they are still as cheap as they were from the start... The capacitors are of OK quality, but I would guess that all eletrolytic capacitors are dead and need to be replaced. It is built around germanium transistors, and the seller cheerily states that they are "selected". Which would probably be neccessary just to get the thing working in the first place... In short: It is a nice piece of DIY kit, but I certainly wouldn´t recommend buying it for using it, for that there would probably be much better mixers around. And if one would like to use it for a practical purpose, I think that there are better mixers available, and they wouldn´t neccesaily cost a fortune. One of my favourite brands (being danish that is not a surprise) is NP Elektroakustik; they made mixing consoles for Radio Denmark, and they are really, really good. And they look nice too: http://broadcastsupport.eu/products/17-audio-mixers/1320-np-elektroakustik-lv28/ I have one at home; I might be tempted to post some pictures of it. But there are a large amount of fine mixers from 1960-1980 around, and it is great fun to see, how imaginative and competent some people were.
  2. The ATN supplies are simple unregulated types, where one of the central components is a 2200 uF capacitor, that is quite prone to ageing and drying out. So normally I would start with changing that. Apart from that individual rectifier diodes can short, or (in extreme cases) the transformer can be shorted. But a good bet would be the capacitor; changing it is easy and cheap, and the same goes for diodes. The exact values and diode types are uncritical; just about anything will do. After changing the capacitor, it will probably perform as new (or better). On the ATN supplies there are two fuses, one for the 110 V section and one for the 220 V section. The 220 V section fuse is designed for half the max. current of the 110 V fuse, so if you replace a burnt 110 V fuse with the 220 V fuse, it will probably die quickly even if there is nothing wrong. So be sure to replace with the correct breaking current...
  3. A very nice machine... It is nice to see one of the early versions, where the pilot system was not really implemented yet, and there was room for the huge, but very well designed head covers. On most/newer Nagra III without pilot, you can see that it is actually just a III without the pilot head fitted, on this model there is no room for a pilot head. I also shows how brilliant the Kudelski designers were: Even on this relatively early version, the design seems "mature", and exactly the same design, with very small changes, were kept until the model was phased out 10 years later. There is absolutely no "prototype"-feel to it; they did their homework and designed it correctly from the very first products... Is it still working? It is amazing that the blue Philips capacitors are still working (they are on all mine), when other companies had serious problems with dried out and/or leaking capacitors. The only defective capacitors on any Nagra seems to be the english Plessey-capacitors in the ATN power supplies. but in the recorders they just keep on working.
  4. It seems that the one I had was one of the newer types with a ruby blade... Here is a picture of one:
  5. MarkC: I think that the erase head is made of a very hard resin material. I have rarely seen a worn erase head, so they seem to be quite robust... I have only once seen a recorder with the ruby tape cleaner installed, so it can´t really be that necessary... But a nice little accessory, and who would say no to having a ruby knife? The QDAN is a take identifier device, so that you can (when you record) assign a take number, and when you play back the tape, the corresponding take number is displayed on the QDAN unit. I have been looking for a manual describing it more in detail, but until now it I have not found anything. I will get back if something comes up. And, as JBond suggests, anything with a nixie tube is by definition great to have.
  6. The limitation in using the pilot signal for driving a "tape counter" circuit is that it is a mono phase signal, i.e. it will describe the speed of the rotation, not the direction. For that, you will need a kind of biphase signal (like the standard biphase signal used for controlling 35mm projectors etc.). So if you just read the pilot signal, it will only work if you don´t rewind. But if you slave you recorder to a film camera, which hopefully never rewinds, it will be accurate...
  7. MBM: Right now there is a Radio Denmark Nagra IS for sale here in Copenhagen: http://www.dba.dk/baandoptager-nagra-is-tran/id-1029164654/ My experience with dba. dk is that it is normally pretty safe (it is owned by eBay). Radio Denmark (DR) machines are usually quite well maintained; I have not seen any major faults on any of my DR IS recorders, apart from one with a rumbling capstan bearing... If you want a couple of "local eyes" on the recorder before buying, I could try to set up a meeting with the seller (who I know nothing about, so I will only be able to vouch for the recorder itself...)
  8. 600mhz equipment resale?

    I have frequently been working in Mali, and on the last couple of trips I have had a bunch of "EU illegal" Audio Limited and Sony transmitter/receiver sets in the suitcase as donations for the local film institute and the TV station. They are really competent people down there, but purchasing new equipment is often not an option, so the surplus gear have come to good use down there... It is very satisfying to give good equipment a second chance, and at the same time helping people.
  9. A bit of mixed comments (after all there are quite a few differents subjects here...): I have enclosed a couple of photos of resp. wide- and narrow track heads. They show a wide track recording head and a narrow track playback head (with space for a pilot track in the middle of the tape. My apologies for the awful pedicure on the pictures... Just for illustrating the somewhat strange choices of the Stelladat, I have also enclosed a couple of photos of the inside of the Stelladat. From the bottom view photo of the base board it is obvious that Sonosax had no second thoughts about selling a near-prototype device. It shows that the company simply didn´t have the resources for designing a product that advanced, and when they tried, they couldn´t afford to scrap obsolete versions; they chose to add a multitude of corrections in stead. If you wanted to control the recorder using the AUX-connector? Too bad, it isn´t connected to anything on the inside. And the list of strangeness is long... But I still like it; despite (or because of) its shortcomings it is a wonderful transitional device, and as a stand alone DA converter it sounds really good. If I had two of them, I wouldn ´t hesitate to send one of them to live i JBonds great collection, but I have grown quite fond of it, and I hope one day to succeed in fixing it one day. I generally collect Nagras, but some recorders are too exquisite to not own. The same goes for the Mandozzi DART-2 recorder, also a little swiss masterpiece. Only 32 kHz sample rate, but with at fantastic build quality and, despite the low sample rate, a great sound. It´s also swiss, so at least there is a swiss theme. And David: If you ever get to scan the Stelladat manual, I would love to see it.
  10. I would guess not, as the audio path is the same in both models. The only (very hypothetical) problem could be crosstalk from the TC system, but that will be easy to detect just by listening. Be aware that there could be quality differences between unmodified IV-S recorders, they were delivered with heads for either 2 mm track width (for pilot/TC models) or 2,75 mm track width (for non-pilot machines). The larger track width gives a slightly better S/N ratio, so if you compare a wide track IV-S with the X4S, the IV-S will be a bit better. But, to make things even more complicated, non-pilot recorders were sometimes fitted with narrow track heads, so that there was compatibility between pilot and non-pilot machines... So, to quote Beastie Boys: Check your head.
  11. Speaking of Stellavox/Sonosax, I have a problem, that somebody out there can help me with? Some years ago I got a Stelladat with a defective transport system. I have been unable to find any information (service manuals, user manuals, schematics, anything...) about it. Does anybody know somebody who has any experience in servicing the Stelladat? This particular recorder was scrapped from a rental company after its bankruptcy, as it was alway defective. It went for repair, worked a couple of days and then died again, was sent for repair... and declared dead. But it would be nice to get it running again, for for the fun of it. As MBM writes about the interior of the Stellavox AMI48 mixer, the Stelladat looks great from the outside, but on the inside it is a bit of a mess.. And sorry for hijacking the Nagra thread; I promise to help it back on track.
  12. I am trying to find out more about the Sound Assist device; it seems that the manufacturer is still in business (Danny Natovich Ltd.). I have contacted them in the hope that somebody still knows anything about it. I have some ideas about its functionality, but I would like to know more. And when I do that, I will certainly get back with a description. As a comment on the recent posts about the Nagra IS versions, I have found a couple of brochures describing the various versions. Or some of them... I can see that my own IS-TLSP is not mentioned, so who knows what other versions are around? But again: The Nagras were very costumizable, making it possible for clients to get the machines suited perfectly for their individual purposes. So countless variations were made. The most interesting variation is the ISS for playing back SN tapes. On the pictures of the heads and the tape path, it can be seen that the Nagra machines were a very universal platform. On the ISS-recorders all the mechanical parts are he same as for 1/4" tape versions, only a few parts are different or just modified. Except of course for the jog/shuttle function, which is exclusive for the 1/8" versions. A year ago I was in contact with a French owner of an ISS, but unfortunately I am convinced that he wouldn't part with it cheaply, and I am not a rich person. But I completely understand him... Nagra IS konfigurator 1.pdf Nagra IS konfigurator 2.pdf Nagra IS-N brochure 1.pdf Nagra IS-N brochure 2.pdf
  13. Speaking of "Yacht"... One of my all-time quirky favourites: The Nagrafax. It was one of the first fax machines dedicated to maritime use, designed på print out weather charts via radio. This one actually still works fine, and it is still possible to find old weather charts uploaded to YouTube as mp3-files. Stefan Kudelski was a keen sailor, and he saw the need for a robust device for printing out "on line" weather info while at sea. This particular Nagrafax was used by the Bundeswehr; I think that they had quite a few of them, as I have seen other BUND-marked devices. It has an internal demodulator, so it will accept a standard audio signal (with encoded data), but the image quality is not really great. But still: It is a Nagra, as the rear view shows: It is the same motor as in the tape recorders.
  14. I don´t know if the Nagra D qualifies as a rare Nagra? In Denmark only three of them were sold, so in my local context they are a bit rare. I have a couple of them, and even compared to present devices the Nagra D is remarkably well sounding. And mechanically it is also a joy to behold, so I might open one up and post some pictures...
  15. When I saw a Nagra 4.2 IRT on eBay a couple of weeks ago I immediately became intrigued by it, and as luck would have it, I managed to buy it for an OK price. Fortunately the owner is also from Denmark, and he even shipped it for free. So now I have an IRT, and I have begun finding out what is so special about it. Apart from having green knobs... First of all I have been on a hunt for information on why it is named "IRT", and soon I found out that the IRT stood for Institut für Rundfunk Technik. This led me on what I presume is actually a wild goose chase, because I have now found out two things: - The modification is not necessarily made by IRT - The IRT does not denote the manufacturer but rather the type of timecode it accepts. The last point is actually quite interesting, because I thought that the only timecode in play here is the SMPTE TC (as in the Neil Stone and Harvey Warnke mods), but there was also another, lesser known, timecode format, (briefly) known as the IRT timecode. The IRT timecode format was meant as a way to create a timecode information that could be printed directly on the film in the camera (16 mm). It predates the somewhat more advanced Aaton timecode, which was widely used, but at the time of its conception, the technology was not so advanced that a great deal of metadata could be written and read. The creators of the IRT TC settled for marking one frame each second, because then they could write a complete set of metadata once a second (time, date, camera number etc). The information was printed between the perforation holes, 4 bits between each set of holes. This gave them 80 bits to work with, the remaining empty spaces were used for synchronisation. To cut a long story short: Both the camera and the recorder had TC generators, and they could then be synced using an external master clock generator. It was clever and not too hard to implement, but it did have one major drawback: If you were to make an edit within an image sequence of the 25 frames, the individual frame number would be lost... That, and of course the fact that the better/smarter format does not always guarantee success, meant that the IRT was not very used. But back to the present, and back to my 4.2: When I opened the recorder and checked the large "unoriginal" card mounted, I was a bit surprised to find out, that it was actually just a quite large carrier board for a normal Kudelski 50/60 Hz crystal generator. As you can see in the photo of the connector board, only a few of the pins are used. Another interesting thing is that the underlying connector board is also quite unusual. It has, in the best swiss and german tradition, all connection names printed on the board, indicating that signal-wise there are a lot of extra potential functionality hidden in this machine. If you have the proper IRT TC board... In the pictures the two original Kudelski boards (a synchroniser and a clapper control board) are removed to show the base board, so normally this recorder functioning as a standard 4.2. It seems that the Kudelski/IRT/whoever people who devised this modification made a rather costumer friend design. They knew that the IRT TC function would not always or rarely be used, so making an expensive recorder that was tied to an experimental TC format would be a commercially very expensive experiment. It would probably leave a lot of costumers quite disappointed, should the IRT format die a quiet death, making you an owner of a very expensive non-sync 4.2 So they made the modification optional and user-interchangeable: If you use it as a normal pilot/crystal controlled 4.2, you use the simple generator board. If you want to use it with IRT TC, you put in the dedicated IRT module. In that way your investment was safe whatever happened. I have recently seen another 4.2 with green knobs and stereo heads, and in this recorder a normal Kudelski generator board was somewhat unceremoniously put in to replace the custom carrier board. So I guess that the missing IRT TC boards is testament to the failure of the IRT format, and that most IRT recorders lived as normal 4.2 recorders. And this brings me to the next question: Does anybody have a IRT TC board? And who produced it? I hope to find out; not because I would have any use for it, but I always like to know more about all these deceased formats, that are left as roadkill along the technological highway. The attached pictures are just meant as illustrations, but one detail should be mentioned: On the picture of the main control switch, you can see an extra LED marked "Zeitcode Ein". It seems that this LED would flash if the TC generator was working properly, and it had been synced recently. So in this case, a flashing red light actually is a sign of safe operation... I know that this is a bit nerdy (my wife certainly thinks so), but I hope that at least a few people are also thrilled by the adventures of reverse engineering and information gathering, not on the Dark Internet, but certainly on the not so sufficiently lit areas. And in a few years some of the history is lost completely; I would like to do my bit to at least scratch the surface and document what I find out... Added note: I have just noticed that the part no. format on the carrier board is the same as the one used by Kudelski. So it might be an actual Kudelski product.