Tape recorder

Revox A77 MkIII (1978)
Revox A77 MkIII (1978)
Tonbandgerät von Saba
tape recorder of Saba
tape recorder of Nordmende
tape recorder of Nordmende (interior opinion)

a tape recorder serves the similar sound recording on tape material. The latter consists of thin plastic as substrate, which is coated with iron - , ferric oxide - and/or chrome oxide crystals with a magnetizable layer.


Table of contents

history

it gave historically since the 1930er years first only coil devices, which work with loose tape material. In the start time this was simple steel wire. In the course of the 1930er yearsbecomes acetate - volumes with width of 6.5 mm develops, which are rolled up on more or less large coils. One calls these first devices also full trace devices, because the whole range is used only for a trace. The volume speed amounts to first 76 cm/s, later 38 cm/s.

Around 1943 there are first half trace devices. Only one half of the volume is used and the coil at the tape end is turned; so one can double the play time.

At the beginning of the 1960er years quarterly PUR-devices are developed. Within the home range the volume speed sinks on 9,5 cm/s. These devicesmake possible the Stereo-Aufzeichnung.

Center of the 1960er-Jahre multi-trace tape recorders are introduced - first 8-Spur-Geräte with a range of 1 tariff (1 tariff = 2.54 cm), in the advancement went this up to 48 traces on 2-Zoll-Band (5.08 cm). Hereby it is possible, 48 individual sources of clay/tone simultaneous orsuccessively to take up, and one assigned thus with the Ur-admission each source of clay/tone to a trace. Thus merging can later happen and repeat up to the satisfaction. There were attempts also with up to 96 traces. Spulentonbandgeräte are used today hardly still in the private sector, but onlystill within the professional range, particularly with the broadcast and in Tonstudios; in addition, there already with removing tendency.

Into the 1960er-Jahren the tape decks with the Compact cartridges (audio cartridges) arise. They are clearly more comfortable and by it housings “reliable” in the handling. They cooperatesubstantially narrower tape material (3.175 mm), which settled in the start time much in worse clay/tone quality, so that these devices are used less first particularly as dictating machines and for music recording. That changes rapidly, above all, as CrO 2 - for tape material is developed, with also HiFi - quality becomes possible. By the use of intercarrier noise suppressor - systems (Dolby, HighCom (Telefunken)) the clay/tone quality could be substantially increased again. Likewise new clay/tone heads were developed, which had a very high service life (glass ferrite head). Thus the tape decks replaced the Spulentonbandgeräte in the private sector. Today becomealso these devices ever more rarely assigned. Into its domain burned CDs penetrates and/or. DVDs, the mini disk as well as computer non removable disks (v. A. with MP3-Musikdateien) forwards.

one has structure

and technology according to standard on the left of the completion coil with the supply, in front in the center the clay/tone heads(S. and) and the Capstan wave (S. and) and on the right of the take-up reel. Within the professional range also open tape reels are used, as Wickelkörper serve the AEG Spulenkern (so-called Bobby) and/or. the NAB - Ring.

For the recording two clay/tone heads serve. First the volume runs by to that an erase head,a relatively broad head gap exhibits and with high frequency far beyond audible frequencies - usually over 80 kHz - one feeds. With cheap devices already times with a continuous field one deletes, which reduces however the photograph quality. The actual recording takes place with a Sprechkopf, thata somewhat broader head gap than the hearing head exhibits, in order to make possible a sufficient Durchflutung of the magnetizable Materiales and thus sufficient level and signal-to-noise ratio. The low frequency which can be noted gets still another certain portion of high frequency (the same as with the erase head) added, in order to avoid hysteresis effects, the so-called. Bias. For the rendition serves a hearing head, which should have rather as narrow a head gap as possible, in order to achieve as high a critical frequency as possible. With more inexpensive devices only one combination head is used both and hearing and and Sprechkopf, then after a compromise for both requirementsone lays out.

The actual tape drive is not made by the tape reels, since this would lead in view of the constant changes of diameter of the tape windings to speed fluctuations. The constant volume speed is ensured präzisonsgefertigte steel shaft in close proximity by perpendicularly a standing, to the Sprechköpfen, which has an exactly specified diameterand also high-constant number of revolutions rotates. To these the volume is pressed in slightly by a fitted with springs rubber role (feed roll). This wave calls one Capstan - wave. The tape reels are then only there to complete and roll with easy course on the other side the tape material up with slight resistance.With home devices this takes place usually via mechanical slip clutches. With (half) professional devices (z. B. ReVox) takes place the drive with three engines, from which two for the torque of the two Wickelteller and third are responsible for the drive of the Capstanwelle. The volume speed with Spulentonbandgeräten9.5 amounts to cm/s or a multiple of a power-of-two number of it (19, 38, 76 cm/s) or fractions (4.75 cm/s) of it. The value 4.75 cm/s is used also with audio cartridges. Videokasetten run in standard speed about half so fast (2.39 cm/s).

Each volume speed has its special optimal Emphase.To this change of the frequency response a standardized time constant belongs. With the admission high frequencies are raised (Vorverzerrung or Präemphase), which are lowered during the rendition in the same relationship by the Entzerrung (Deemphase) again.

important manufacturers of tape recorders

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