Magnetophone
Magnetophon was originally the name for some magnetic sound recording and playback devices ( tape recorders ) developed by AEG . Due to the great popularity of these devices, magnetophon was often used as a synonym for tape recorders from other manufacturers and thus became a generic brand name .
In 1928 Fritz Pfleumer developed a device with which he could play the "phonetic letters" he had previously invented during presentations. After Pfleumer and AEG had reached an exploitation agreement for the tape in 1932, AEG commissioned the engineer Eduard Schüller to develop a series-capable player for the tapes. Because Schüller had considerable difficulties preventing the tape from tearing during fast-forward and rewinding, AEG relocated development to the AEG test laboratory in Berlin , under the direction of Theodor Volk , who already had experience with a similar problem with film projection devices. In 1935, the so-called three-motor drive was developed at short notice in cooperation with BASF .
The three-motor drive had a drive motor for playback and one for fast-forward and one for rewind. That solved the problem.
In 1935, AEG and BASF jointly presented the new device to the public under the name Magnetophon K1 at the 12th Great German Radio Exhibition beginning on August 16 . The interest, especially from the Reichs-Rundfunk-Gesellschaft , was great. A fire that broke out on the third day destroyed not only the exhibition hall, but also all five (according to other sources 4) prototypes existing at that time.
Originally, the AEG assumed, because of the modest sound quality, that the real benefit of the magnetophone lay in the recording of dictations. With the recording of a concert by the London Philharmonic under the direction of Sir Thomas Beecham in 1936 in Ludwigshafen am Rhein , new areas of application emerged. Broadcasters , who had previously used wax discs for sound recording, were interested in the new technology and were increasingly using it.
Until then, the strong clinking and hissing caused by the hysteresis of the magnetic induction in ferromagnetic materials was the main problem . In 1940, the high-frequency bias was found by chance , which circumvents this effect, resulting in a hitherto completely unknown fidelity of sound.
The Magnetophone were sought after the war, the Allied soldiers loot. The US industry was also interested in the technology, which was unknown outside of Germany, and copied it, as magnetized wire had still been used for sound recording in the USA up to that time .
Magnetophon was a registered trademark for tape recorders from the Telefunken company . Magnetophon has been a registered trademark for tape recorders from Kai Hilpert, Hamburg, since 2008 .
Magnetophon devices from AEG
Magnetophon K1
In 1935, AEG presented the world's first industrially manufactured tape recorder at the radio exhibition in Berlin. During the fire in an exhibition hall, all 5 (or 4) prototypes were destroyed. However, there were still enough individual parts in the factory to be able to make another copy. The tape used was 6.5 mm wide; the belt speed was 1 m / s; the device could record frequencies up to 6000 Hz. The playing time of a tape was about 20 minutes.
The great advantage of the tape recorder over the record was the ease of recording.
Note on the width of the tape: When American companies took over the principle after 1945, they used tapes 1 ⁄ 4 inch wide, which is 6.35 mm, 0.15 mm narrower than the previous tapes. Since wider tapes, played on devices for narrow tapes, developed wear on the edges, all devices (and tapes) then had to change to the American size.
In technical jargon, the 1 ⁄ 4- inch tape was quickly referred to as "shoelaces" because of its originally brown color . Generations of sound engineers and sound technicians have used this term up to the present day, but for younger colleagues it has only been a technical term for archive material since the introduction of digital sound recording methods (e.g. DIGAS ) in the early 1990s.
Magnetophon K2
In 1936, AEG presented the K2, which had been further developed from the K1. It consists of four parts: drive, amplifier, speaker, microphone. Externally visible differences to the K1 are the arrangement of the four switches on the left (all four in a row, with the K1 three in a row and one behind) and the shape of the cover of the tape heads.
This magnetophone was used to record the so-called “Beecham Concert” with the London Philharmonic Orchestra under its founder and director Sir Thomas Beecham in the Feierabendhaus in Ludwigshafen on November 19, 1936 .
Several images or excerpts of color photos are circulating on the Internet, which are presented as "... the first K1 magnetophone from AEG ...". These are always images of the K2 model from 1936, on which the tape ruler on the left reel plate is also not present. The pictures come either from page 2 of the publication "Telefunken - Tape recorders Magnetophon - a hobby without limits", A4 format, four-color from 1962 (the picture only shows the drive without amplifier, microphone and loudspeaker), or from the middle of the In the 1980s, recordings made for BASF product brochures in a Frankfurt photo studio (all four parts of the K2).
Magnetophon K3
In 1936 AEG presented the Magnetophon K3 . The "K3" was one of the first portable tape recorders in the world. A carbon microphone, amplifier and loudspeaker were included in the delivery. The entire system weighed approx. 50 kg.
Magnetophon K4
In 1938 the Magnetophon K4 was created, which quickly found widespread use in radio studios, as the tape offered clear advantages in handling and storage as well as a significantly longer playing time compared to the previously used wax plates.
The belt speed was 77 cm / s. With a tape length of 1,000 meters, this resulted in almost 22 minutes of recording time. The value of 77 cm / s chosen by the AEG remained the standard speed in broadcasting for many years. When AEG magnetophones came to the USA after the end of the war, their first own models were largely based on the AEG devices. The conversion from 50 Hz to 60 Hz alternating current network (different motor speed) and from the metric dimensions of the AEG to the inch dimensions customary in the USA resulted in a slightly lower belt speed of 76.2 cm / s (equal to 30 inches) per second), which soon caught on internationally. Advances in device construction and tape production allowed it to be halved to 38.1 cm / s as early as the early 1950s, which became the new standard in the radio and studio sector that was valid until the end of the era of analog tape technology. By halving it further, the values 19.05 cm / s, 9.5 cm / s and 4.75 cm / s were obtained, which became important in the amateur field.
Magnetophon K7
In 1943, the K7 magnetophone first used the high-frequency bias magnetization discovered by chance by Walter Weber and Hans-Joachim von Braunmühl in 1940 , which considerably reduced tape noise and, above all, clinking . Only since this device were the recordings clearly superior to other techniques, such as direct editing. At that time radio listeners could no longer distinguish tape recordings from direct transmission (there was only “moderate” quality on long wave and medium wave ). With a device of this type, equipped with a 2-track head, the first stereo recordings were made in 1943 with the help of two Neumann microphones . Some of these tapes have recently been rediscovered in Russia.
Magnetophon AW1
1950
Magnetophon AW2
Early 1950s. The AW stood for A Recording / W Playback.
Only about 300 copies of the AW2 are said to have been built, mostly in sand yellow.
Magnetophon KL15
In 1951, AEG presented the KL15, the first tape recorder of the Magnetophon series developed for private users, at the industrial exhibition in Berlin . The device cost 770 DM (corresponds to about 2,000 EUR today)
The belt speed was 19 cm / s. The device weighed around 20 kg. While the mechanics and electronics for recording and playback were installed in the chassis, the audio amplifier, including loudspeakers and controls for bass, treble and volume, was located in the lid of the device (hence the name "lid amplifier"). With a record player set available for 45 DM surcharge, consisting of tonearm and turntable, you had tape recorder and record player in one. The turntable was placed on a shaft located behind the head carrier, the tonearm was placed on a bracket on the right rear of the chassis.
The tape chassis was also used as additional special equipment for luxury music chests with 10-record changers.
Magnetophon KL25
The Magnetophon KL25 appeared in 1953/54 as the successor to the KL15. In contrast to its predecessor, the entire electronics were now housed in the chassis, together with the mechanics and the loudspeaker. The belt speed was 9.5 cm / s. The device had three heads (erase head, recording head, playback head) in mono half-track technology. The track position of this model still corresponded to the German standard, that is, recording and reading was carried out in the lower half of the tape. In later models, AEG-Telefunken went over to the international standard in which the upper half of the tape is recorded and read; earlier KL 25 and KL 15 could be retrofitted to international standards by the factory customer service.
Magnetophon KL65
The Magnetophon 65KL , published around 1955/1956, is a case device in a plastic housing , with half-track technology and a frequency range of 60 to 10,000 Hz at a tape speed of 9.5 cm / s. Half track technology means that only the upper half of the tape is recorded. After passing through, you can swap the coils and turn them around so that the track below comes up and can also be played on. This doubles the total playing time and saves you time-consuming rewinding.
The "KL65" has a speaking head (SK, recording head), a playback head (HK, ear head ) and an erasing head . It can be equipped with spools up to 13 cm in diameter. The playing time is 2 × 45 minutes when using 260 m long-playing tape. The device has the dimensions 308 × 125 × 234 mm and weighs 7.2 kg.
Magnetophon KL65KS
The approximately 1,956 published half-track recorder Magnetophon KL65KS was a single-engine drive with asynchronous AEG internal rotor and flat belt-driven Capstanschwungscheibe and Aufwickeltellerantrieb from the capstan by slipping belt equipped. The belt tension control was carried out via lever-operated brakes . The device also had an electromagnetically assisted tape pressure. The tape speed could be changed in later models from 9.5 to 4.75 cm / s, which doubled the playing time again. The frequency range reached from 60 to 11,000 Hertz at 9.5 cm / s, with a dynamic range of 45 dB. The wow and flutter was only about 0.3%. The maximum coil size was 13 cm. "Start" and "Stop" could be switched remotely via a cable and the device also offered a control loudspeaker. The KL65 also had a snapping pause button and a record lock that prevents accidental pressing of the record button. The lock is unlocked by pressing a second button.
Tubes used: EF 86 (microphone and playback preamplifier); ECC 83 (A / W repeater); ECC 81 (push-pull quenching generator for quenching and HF pre-magnetization); EL 95 (low frequency output stage); EM 71a (magic eye in V-shape for level control). Due to the tube technology, all inputs were very high impedance on the impedance side (megaohm range) and thus incompatible with the emerging transistor technology, which worked with lower impedance (47 kilohm range).
Magnetophone 70
The Magnetophon 70 was a greatly simplified half-track mono version of the Magnetophon 75. The option to switch to the second tape speed of 4.75 cm / s was omitted here. A tone control , pause button and record lock have also been dispensed with. The tape counter was replaced by runtime markings on the cover plate for rough orientation.
Magnetophon 75-15
The Magnetophon 75-15 appeared in the second half of the 1950s and was largely identical to the Magnetophon KL65 in terms of mechanics, electronics and equipment, so it allowed recording and playback in half-track mono technology. The main difference was the maximum reel size of 15 cm compared to 13 cm for the KL65 and thus a longer playing time. The Magnetophon 75 remained in the range for many years and has seen some changes over time. The round "magic eye" of the first models with the display tube EM71 was replaced by the EM84 with the rectangular display field ("magic tape"). The vacated space was used for a tone control "sound screen", which did not exist in the earlier version. A number of other versions were derived from the M 75 (Magnetophon 70, 76, 77), with the mechanics and electronics being taken over from the KL65 / M 75 as far as possible. The pull magnet also enabled an externally switchable pause function. Between the erase and A / W heads, a tape calming roller reduced longitudinal tape vibrations (goal: lower modulation noise).
Magnetophone 76
The Magnetophon 76 was the quarter-track mono version of the Magnetophon 75, recognizable by two pushbuttons (gray and red) in the top cover of the audio head to choose between track 1 and track 2. Mechanically, the M 76 was completely identical to the M 75. In terms of equipment, the M75's tone control was replaced by a micro-radio input selector. Electronically, it differed from the M 75 in that it had an additional amplifier stage, fitted with a transistor OC603 or OC604, which was placed in front of the EF86. Thanks to the 4-track technology, a maximum playing time of 12 hours and 40 minutes could be achieved with full tape use of the 15-reel.
Magnetophon 77
The Magnetophon 77 was the quarter-track stereo version of the Magnetophon 75. It came on the market at the end of 1959 and enabled each of the two sound tracks running in one direction to be recorded and played back separately.
Magnetophone 85
The Magnetophon 85 joined the KL65 and M 75 in the second half of the 1950s and was the top model in the product range. Like these, it had a tape counter, pause button and record lock, the maximum reel size was 18 cm. The drive differed significantly from the smaller models and allowed speeds of 9.5 and 19 cm / s. Recording and playback took place in half-track mono technology. Of these three models, the M 85 had the longest production time and remained in the range until the second half of the sixties. It experienced some changes in the process. The round display tube EM71 of the first copies was replaced by the EM84 with a flat, rectangular display field. The space freed up was used for a controller with which a second signal input could be controlled separately. The device thus had a mixer function.
Magnetophon 96
The machine had three tape speeds: 4.75; 9.5 and 19.5 cm / s.
Magnetophon 105/106
Around 1964, the half-track mono model Magnetophon 75 was replaced by the Magnetophon 105. The drive and electronics remained largely unchanged, but the plastic case of the M 75, strongly rounded in the style of the 1950s, has been replaced by a square housing in a more modern design. The successor to the quarter-track mono version Magnetophon 76 came on the market as Magnetophon 106.
As early as 1965, these models were replaced by the devices of the 200 series (e.g. Magnetophon 200, 201, 202, ...) with a completely newly developed drive and fully transistorized amplifiers, which, in addition to the classic case devices, were now also available in versions for vertical operation.
Magnetophone 200
2-track device with a tape speed of 9.5 cm / s; maximum coil size 18 cm; Weight approx. 9.5 kg
Magnetophon 201
4-track device with a tape speed of 9.5 cm / s; maximum coil size 18 cm; Weight approx. 9.5 kg (was also available with a case in walnut veneer with a smoked glass hood under the name Magnetophon Berolina)
Magnetophon 202/212 Automatic
The M202 / 212 was built from 1968 to 1971. It had 2 or 4 tracks and an automatic recording, a switchable front speaker and a tape speed of 9.5 cm / s; Side connections for radio, microphone, record player, headphones and speakers. The frequency response was 60-13000 Hz.
Magnetophon 203
This model was available in different versions. The only devices called "Magnetophon 203" had two tape speeds (4.75 and 9.5 cm / s) - in quarter-track technology. Exceptions (probably only called in 1968) were the Magnetophone 203 "Studio" 2 and 4. These had 9.5 and 19 cm / s (see below).
Magnetophon Studio
This device was an offshoot of the M 203, it was first called "Magnetophon 203 Studio", later (from 1969?) The number 203 was omitted. It had a tape speed of 9.5 and 19 cm / s and was available as a half (Studio 22) or quarter track version (Studio 44). It had a housing in wood decor. The hifi standard DIN 45 500 was met at 19 cm / s.
Magnetophon 203 de luxe
Technically the same as the 203, this device had a walnut veneer housing. The cover and the buttons were made of silver or bare aluminum. The lettering "Magnetophon 203 de luxe" was placed thinly below the potentiometer.
Magnetophone 204
M204 first generation
M204 TS
M205
M207
M207 to take away
The M 204 was initially only available as a quarter-track machine for vertical and horizontal operation. Later models (M 204 TS 2 and 4) were optionally available in half and quarter track versions with a slightly different design. The last version had three belt speeds (4.75, 9.5 and 19 cm / s).
Magnetophone 205
The M 205 is the same device as the M 207, only without an amplifier and loudspeaker. It had to be connected to a stereo system.
Magnetophone 207
The M207 was built from 1969 to 1972. It was a quarter-track stereo device and had a built-in audio amplifier with 2 × 2.5 watts. 3 speeds 4.75 / 9.5 and 19 cm / s and a frequency response of 40 to 18000 Hz at 19 cm / s. The scope of delivery included 2 removable loudspeaker boxes.
Magnetophon 210 or 230
In keeping with the spirit of the times, the models 201 and 203 were offered at the beginning of the 1970s with a separate on / off switch and flat control dials instead of the rotary potentiometer (volume with on / off).
Magnetophon 250 acusta hifi
Around 1970 the magnetophon 250 with half-track stereo technology (stereo recordings on full bandwidth) and two tape speeds was offered as a tape recorder for the top stereo system "acusta - hifi". It was the only magnetophone of the 200 series to be equipped with three tape heads (rear tape control). The simple single-motor drive was retained, however.
Magnetophon 300/301/302
The three portable devices of the 300 series were particularly popular with young buyers, as they could be supplied with 5 mono batteries, lead gel accumulator or mains power (via an external power supply unit) and also made musical entertainment possible on the beach and in the garden. All had the same compact housing with push-button operation and could be equipped with spools up to 13 cm in diameter. The 300 and 301 models were introduced in 1966, the 302 came a little later. The M 300 was a half-track mono device with 9.5 cm / s. The M 301, available until 1969, was the quarter-lane version of it. In addition to black, the M 300 was also available in the special colors white, green and red from 1969. Later only the M 300 (TS) and the M 302 (TS) were offered, which had two belt speeds. A stereo version was not in the program. All tape recorders of the 300 series were characterized by a drive specially designed for mobile operation, which had two counter-rotating masses and was therefore "spin-proof". The engine was electronically controlled according to the same principle as in the Uher Report. The devices had a sturdy die-cast chassis.
Magnetophon 500/501 DeLuxe
The M500 / 501 was a home tape recorder with 2- or 4-track technology that was built from 1969 to 1971, otherwise the two devices were identical. Recording and playback were only possible in mono, playback via a built-in amplifier with 2.5 watts. It had a belt speed of 9.5 cm / s and a frequency response of 60 to 13000 Hz. It could accommodate reels up to 15 cm in diameter. The device had a so-called panorama counter, in which a pointer on a tape was moved over a labeled scale on the front. The housing parts and the levers inside were made of plastic (PU?), The outer cover of metal.
Magnetophon 3000 Hifi
Device like the 3002, only without a built-in amplifier.
Magnetophon 3002 Hifi
Quarter-track stereo device with 3 tape speeds and servo-magnetic push-button control.
Mains: 110/127/220/240 V, 50 Hz, switchable 117 V, 60 Hz, power consumption: 20 W (idle), 65 W (full load)
Heads:
- 1 speaking head SK (recording head) 2 × 1 ⁄ 4 track
- 1 playback head HK (ear head) 2 × 1 ⁄ 4 track
- 1 erase head LK 2 × 1 ⁄ 4 track
Equalization according to DIN 45513
Belt speed: 19 cm / s ( 7 1 ⁄ 2 ″), 9.5 cm / s ( 3 3 ⁄ 4 ″), 4.75 cm / s ( 1 7 ⁄ 8 ″) switchable
Spool size max. 18 cm
Counter
built-in power amplifier 2 × 20 W sin, 2 × 35 W music
Recording inputs:
- Tuner / radio (2 × 4 mV) at 40 kOhm
- Microphone 2 × 0.15 mV at 2 kOhm
- Phono / tape 2 × 100 mV at 1.0 MOhm
Playback outputs:
- Radio 2 × 0.7 V
- Headphones 2 × 2.5 V
- Monitor 2 × 0.7 V
Adjuster:
- 2 × level microphone
- 1 × radio / phono level control (trick function)
- 1 × presetter
- 1 × heights
- 1 × depths
- 1 × balance
- 1 × volume
5-function switch:
- 0 / trick
- Echo / multi
- A (in front of the belt) B (behind the belt)
- Stereo / mono
- 1/4 and 3/2
Weight about 16 kg
Magnetophon C2100 hifi
With dimensions of around 31.5 cm × 27 cm × 8 cm, the device weighed around 5 kg.
Magnetophon 21 R
1 ⁄ 4 ″ studio device with 19 and 38 cm / s tape speed.
This stripped-down editing machine still contains all the functions of the normal M21C, only these were not made accessible on the partially closed front panel of the control unit in order to be able to offer the machines more cheaply.
The M21R drive can be programmed at all speeds of 9.5–19, 19–38 and 38–76 cm / s via DIP switches (mouse piano).
The special feature of the Telefunken M20 and M21 are the special glass ferrite heads, the head gap of which is sealed with a liquid glass bead with the advantage of more than twice the service life, abrasion resistance and insensitivity to dirt. This type of tape head is also available from Studer from spare part number 1.118 ...
All factory numbers from 1100 are series machines, including only pre-series and experiment drives.
The very good, balanced sound with a good bass range due to the asymmetrically long head poles and integrated circuits, which can also be found in Studer machines, should be emphasized .
Magnetophon 23
Portable studio tape recorder
Magnetophon 24
The Magnetophon 24 appeared in 1960 as the successor to the M 23 as a small and portable studio tape recorder. It allows recording and playback in mono technology at tape speeds of 9.5 and 19 cm / s on reels up to 22 cm in diameter. The drive is equipped with three motors, a sound motor and two winding motors. The sound motor drives the sound shaft via a friction wheel. The speed is switched by moving the friction wheel to stepped pulleys of different diameters. The M 24 has three heads for erasing, recording and playback. The heads were optionally available in half-track or full-track versions. Separate amplifiers for recording and playback allow you to listen to what has just been recorded while recording (rear tape monitoring). Four inputs of different sensitivity for microphone, radio, phono and second tape recorder can be controlled separately and thus result in a four-channel mixer. A pointer instrument enables control of the level. The amplifiers are built using tube technology and are equipped with 8 × ECC 81, 1 × EC 92 and 2 × EL 95. The chassis with drive and amplifiers is built into a case which is equipped with a total of four speakers (2 oval speakers, 2 tweeters).
Technical specifications:
- Frequency range at 19 cm / s: 30-18,000 Hz, pitch fluctuation ≤ ± 0.25%.
- Frequency range at 9.5 cm / s: 40–15,000 Hz, pitch fluctuation ≤ ± 0.15%.
- Total weight of chassis and case: 30 kg.
Magnetophon Studio 44 hifi
around 1975
Magnetophon automatic II
- Technical specifications
- Mains: 110/220 V, 50 Hz convertible to 60 Hz
- Power consumption: operational readiness: approx. 8 W, operation approx. 40 W
- Tubes and rectifiers: EF86, EF83, ECC83, EL95 , EM84, 3 dry rectifiers
- Fuses: 110 ... 127 V - 0.6 A medium time lag, 220 ... 240 V - 0.3 A medium time lag
- Belt speed: 9.5 cm / s
- Spool size: maximum 15 cm
- Lane position: two lanes according to international standards
- Running time: 3 hours with double play tape
- Rewinding time: approx. 4 minutes with double play tape
- Frequency range: 40 ... 14000 Hz
- Equalization: according to NARTB
- Dynamics: ≥ 48 dB
- Pitch fluctuations: ≤ ± 0.2%
- Recording inputs: microphone 2 mV at 470 kOhm
- Radio 2 mV at 22 kOhm
- Phono 200 mV at 2 MOhm
- Playback output: radio about 1 V at 18 kOhm
- End switch-off: by switching foil
- Counter: 3-digit with release button
- Dimensions: height 16.5 cm, width 38 cm, depth 30 cm
- Weight: about 10.5 kg
literature
- Friedrich Engel, Gerhard Kuper, Frank Bell, Wulf Münzner: Time layers: Magnetic tape technology as a cultural medium. Inventor biographies and inventions . 4th edition. Polzer Media Group, Potsdam 2020 (e-book, PDF).
Web links
- The three ways to today's tape
- AEG-Telefunken - an unforgettable legend. They were the first well before 1935
- Friedrich Engel: start and finish. (PDF) Retrieved on November 12, 2017 (On the history of the AEG magnetophone and Wilhelm Furtwängler's pioneering role in use).
Individual evidence
- ↑ www.radiomuseum.org
- ↑ This figure was based on the template: Inflation determined, has been rounded to a full 100 EUR and relates to the previous January.