Tinico and Electron 52D

Used Google translator

     Tinico.       Portable Recorder - a toy. Produced in Japan in the early 60's. Dimensions 160 x 64 x 40 mm. Weight 350 g. Power motor 1,5 v, two AA batteries connected in parallel, the power wiring 9 v, battery type PP3. Housing plastic. Kinematics of simple, on one engine, without stabilization of speed. The engine is located horizontally between reel tables, and the shaft, acting on both sides of the engine, rotates either one or the other rubberized reel table. Coil diameter 45 mm (1.75 inches) can hold the reel 10 minutes of work. Circuit collected at 2-type transistors 2SB75. There is one connector jack (3,5 mm) to connect the microphone and earpiece. The volume control there, and erase head is used instead of a permanent magnet. Nevertheless, despite the simplicity of design, the machine makes a good impression, and appearance, and quality of work. It really can be used as a voice recorder. It is also known for producing a replica Tinico named Electra 707 Candid. Perhaps there were other names.
    Electron 52D. (Version on radio tubes)     Soviet copy Tinico. Performed in Poltava in 1968, or 1967. The exact date of commencement of production has not yet been set. Operating Instructions began printing in 1967, and the earliest known instance of the recorder with the serial number 037 dated January 1968. Of course this is not an exact copy Tinico, there are minor differences, and even some improvement. For example, in the winding of the motor is fed 3 v, and recording - playing a 1,5 V, but Tinico always 1,5 v. Circuit collected at three transistors (GT109A - 2 pcs, GT108A - 1 pc), without transformers. Slightly changed dimensions - 160 x 67 x 44 mm, and the case became more angular. Weight has not changed - 370 g. The quality of manufacture of our apparatus is not worse than the Japanese, and works, I think, even better.
    Produced as more complex analogues of the recorder under the names “Monacor”, "Elektra 770", "Star-lite Pocket Mate". On the surface, and structurally they are similar, but in the past has a built-in speaker, speed of the engine, and volume control.
    These were not the only very small toy tape recorders that were produced at that time. For example, "Minipex" from the collection of Roland Schellin, who shared with me these photos. But this device, unlike Tinico and others like it, looks really more like a toy.

 

    Tinico was bought in working condition. It turned out the old batteries, which also pose a collector's interest. Electron 52D was purchased in Russia, and in working condition. It took just spinning the engine by hand to re-establish contact with the oxides of carbon brushes contact the collector.

Video review

For ease of comparison, both sets of structures, in the left column Tinico, and to the right Еlectron 52D. Photos can be enlarged

Tinico designed to work with piezoceramic headset. Electron 52D - dynamic headphones.

Manual and circuit voice recorder Electron 52D kindly provided by a collector and amateur Andrew Sologubov (RV3DOI).

The electrical circuit and the specification of the recorder Electron 52D

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Above I told about the existing dictaphone, and now I propose to present such a recorder on the radio tubes

Tube recorder "Electron 52D"

     Several times I watched in the discussion forums on whether there could be in 1945 portable tube recorders like "Tinico". The answer in all cases is one, such a dictaphone then could not be created because at that time there were no technologies for creating three main components -
1. Miniature electric motors
2. The electronic circuit of the necessary sizes
3. Small anodic and filament batteries, as well as battery power to the engine
     It seemed interesting to me to understand whether the technology was really that bad then. Since I have been interested in old portable equipment for a long time, something I already knew, and I had no doubts about the 2 and 3 points, such technologies at that time were. Already in the early 40's, portable hearing aids were manufactured on the ultra-miniature radio tubes CK502AX, CK505AX and similar pentodes. At that time, there was also a technology for manufacturing printed circuitry on a ceramic (steatite) substrate with screen printing of the appropriate paint of silver tracks and resistors, as well as using open-frame capacitors. During the war, these technologies were secret, but already in 1947 a congress on printing circuit technologies was held in the United States. In the report of this congress, the serial technologies already worked out at that time are presented, see for yourself - Report here. By this technology, very compact schemes were made, partly similar to modern schemes with SMD elements. I will add that such complications were not at all obligatory, and a simple scheme could easily be assembled on the element base of hearing aids.
     Batteries similar to modern AA (click on the link) and compact anode batteries were also available already in the early 40's, and confirmation of this can be found here - Link to the museum of hearing aids and batteries to them. For example, such batteries with a voltage of 22.5 v fit perfectly (click on the link), they were patented in 1942. Most likely at that time, as a magnetic carrier, wire would be chosen for reasons of increasing the recording time. However, we are considering the possibility of creating an analogue of Tinico or Electron 52D, that is, we take for granted the use of a magnetic tape, and accordingly a short recording time, only about 10 minutes. In this vein, the issue of batteries gets an additional "plus", because for 10 minutes there would be enough and not very technological batteries, the main thing that they were small. In general, now I'm talking about commercially produced batteries, but nothing hindered them from making them on a special order of the right size. For example, if you optimize the design of the battery compartment, there will be room for larger batteries, 5 to 10 mm longer and 3 mm thicker. By the way, as a reserve argument, the same Wikipedia reports that the technology of manufacturing "dry" mercury batteries for military use appeared as early as 1942. I did not find the 42-year patent on this subject, but I found patents for "dry" mercury batteries of the 43rd year - Patent #: US002473546, S. Ruben, and the 44th year - Patent #: US002526692, S. Ruben, That is also suitable.
     Little magnetic heads under the tape at that time probably did not have any place to use, but in principle they could make smaller copies of the ones already available. Probably they would be of inferior quality, but still they would work. By the way in "Electron 52D" there is a head almost the size of a stationary tape recorder, there is enough space there.
     There remains a problem with small engines. In this regard, skeptics say that such engines were learned to do only at the turn of the 1940s and 1950s because before that time there were no magnets with the necessary properties. However, if you look again at the Wikipedia, it says that a breakthrough in magnetic technologies occurred in the 30's, and in the early 40's a powerful magnetic alloy Alnico already appeared. From 1943 to 1951, there was no technological breakthrough in this area (click on the link), which means that what they did in the 50th could be done in the 44th. The truth is that in the 44-m there was probably no necessary industrial production. However, if the US government were interested in such a dictaphone, its development should have been taken seriously. That is, for such a small-series spy device, such magnets with the necessary properties could probably be made, at least in small amounts in the laboratory. The very design of the engine is primitive, and there were no difficulties in manufacturing for that time.
     Summarizing, we can say that all the necessary technologies for the manufacture of a tube analog "Tinico" by 1945 were already there. There were not only engineers who would connect them in the same construction. Historically, the miniaturization of technology has progressed gradually, and the first serial portable Tube Recorder Minifon Mi51 (1951) was about 2 times larger than the "Tinico". Perhaps the designers were not ready to step psychologically from huge stationary tape recorders to portable spy recorders like "Tinico". It should also be borne in mind that we are talking about the designers of enthusiasts from private companies, since seriously, at the state level, none at all has dealt with this. Why this happened, the question is still open. By the way, such designs were collected even by radio amateurs, for example, in the magazine RADIO-CRAFT in 1946 an amateur design of a portable receiver on the radio tubes CK505AX and CK506AX using compact batteries about which I wrote above is shown. Description of the receiver with the electrical diagram and pictures can be viewed here.
     Next, I thought that it would be nice to implement this design, not created in the 40s, I decided to make "Electron 52D" with a tube electronic circuit. It was not difficult at all to do this, as for the basis I took a simple and already verified diagram of the recorder "Mohawk Midgetape 44". By the way, this recorder uses the module of the three-tube amplifier of the company "Centralab" made since 1945 using the technology of printed circuits on a ceramic (steatite) substrate, which I mentioned above. My circuit works no worse than transistor, you can even use a speaker instead of an earpiece.
     When studying the battery issue, I made a self-made battery of 30 V from manganese-zinc elements, also of my own making. The construction of elements of 1.5 v is shown in the photo below. The anode current of my amplifier at 30 v is about 0.9 mA, and this battery will last for more than 14 hours of confident operation. I conducted this experiment to make sure that such batteries can be made even at home, and even more so could they be made by Americans who in 1945 had already created an atomic bomb. I am considering American technologies, since they were then allies of the USSR, and such a recorder could be turned over for use as much as other military equipment.
     I will add that the circuit operates normally and at an anode voltage of 22 v, it works at 15 v, and even at 9 v, but in the latter case it is already bad. Serially produced then batteries of 22.5 V would fit perfectly in size, and in tension.

     In the photo above, the wires to the board are not yet soldered, and in the photo below it can be seen that all the spikes on the switches are original, covered with green lacquer. I was able to adapt the wiring to the new circuit so that all visible soldering remained untouched. After the end of the work, the photo session, and the shooting of the demo video, I will return the design to its original state with the original transistor circuit without any trace of my intervention.

During the tuning process, it was necessary to achieve correct generation of the output stage at a frequency of 12 kHz to magnetize the head. To do this, we had to shield the circuit from above and below.

     1 and 2 cascades of the amplifier are made on the original tubes CK505AX "Raytheon" those same years, perhaps even the 40-ies. In the power amplifier, I used a 5672 "RTC" tube since the original weekend pentodes of that time were hard to find. This is a later analog of the CK502AX and similar tubes. In the photo on the right, the module of the "Mohawk Midgetape 44" recorder amplifier of "Centralab" company manufactured using the technology of printed circuits on the ceramic substrate, about which I mentioned above, the dimensions of the ceramic plate is 25 x 24 mm. Similar modules for "consumer goods" began to be produced in 1945, (the same in PDF) and during the war, this technology produced modules for military use. By the way, they have a double-sided print, silver tracks, resistors of current-conducting ink, and capacitors are open-frame. So my board with SMD elements can not be considered more technological, in my opinion the technology "Centralab" is much steeper. However, as I already wrote above, such a simple scheme could easily be assembled and on simple details, as in hearing aids.

The photo below shows an external speaker for demonstrating the operation of the recorder. For ease of use, I placed the speaker in a plastic box from the light filter. It sounds so mini speaker is pretty nasty, but loud, and the recorded voice is clear and legible, which is required from the recorder.

     A homemade 30 V battery is easy to make, but patience and accuracy are needed. Elements of 1.5 v consist of zinc plates with paper impregnated with electrolyte, frames forming the body, a mixture with MnO2, and a carbon fiber veil pasted from above to prevent the mixture from splashing. Carbon veil is useful only for handicraft, in the industrial process, it would not be needed. Zinc plates and a mixture I took from cheap batteries such as PP3, and cut out frames from large SIM cards. New elements are obtained with a voltage of 1.6 v, but a small capacity. The short-circuit current of the freshly prepared element is about 150 mA. At a current of 1 mA, the discharge to 1.3 V occurs in about 14 hours. In the photo below all the components of the structure and the element in assembled form. The thickness of the element is 1.4 mm. My battery is made up of 20 elements, but in fact the battery compartment can hold a battery with a large number of elements, up to 30 pieces, that is, with a voltage of up to 45 v. When using a 45 V battery, the current consumption increases to 1.5 mA, and the volume accordingly increases.

The electric diagram of the tube recorder "Electron 52D"

Demo video

     I tried to explain everything basic as short as possible, but for those who are not too lazy to read more, I will add my thoughts on why all the same, with all the necessary technologies, portable dictaphones were not created by the mid-1940s. I think the reason is the lack of order from the state. Apparently, for some reason, the secret services did not demand such a technique from their governments, maybe they did not know that it could be created, or there were some other considerations.
     In any case, an order from the government for portable spy audio equipment for a long time was not. Even the first truly portable dictaphone "Minifon Mi51" (1951) was created in an initiative order in semi-domestic conditions. He was created by engineer Willi Draheim with the financial support of another enthusiast N. Monske, and later he was also a private company "Monske & Co. GmbH". Dictaphone was a huge success, everyone was surprised at this miniaturization, the secret services also showed interest, and began to use them. Changes in the government's attitude towards this issue became visible after the appearance in 1955 of the following model "Minifon P55". This can be judged by the fact that open publications about the design of these recorders have disappeared. It is probably then the work in this direction began to be financed by the state. If it had happened before. Then the development of this topic would begin earlier and much more intensively.
     That is, I mean that the result depends on the seriousness of the approach. If, for example, in 1944 the US government was seriously interested in creating a portable voice recorder, it would be quickly created with all the necessary components, motors, heads, etc., and much better quality than the tube Electron 52D. Once again, I recall that the atomic bomb was created already in the 45th precisely because it was very necessary. True, it was not created from ready-made technologies, but on the contrary, many new technologies were created specifically for this project. You can certainly say that comparing the atomic bomb with a dictaphone is not correct, but then we can give an example and simpler, for example, radio detonators for projectiles (Radio Proximity Fuze 1943). There, too, there were many problems, but they quickly decided, because it was very necessary. Read how serious was the approach to their development.
     By the way, in the USSR such a state order appeared earlier, as Soviet spies used the same "Minifon Mi51, P55", and it was necessary to arrange the production of domestic special equipment. Perhaps that is why the USSR later became the leader in this field, and unsurpassed samples of audio special equipment were created, for example, the wire recorder "Liliput", which had no analogues in the world. I will add that I made my conclusions on the basis of public information, something I may not know, and accordingly I can make mistakes.