Nagra I (1)

Kudelski SA; Cheseaux-sur-Lausanne

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  • Year
  • 1951 ?
  • Category
  • Sound/Video Recorder and/or Player
  • Radiomuseum.org ID
  • 304578
    • Brand: Nagra

 Technical Specifications

  • Number of Tubes
  • 4
  • Valves / Tubes
  • Main principle
  • Audio-Amplification
  • Wave bands
  • - without
  • Details
  • Tape Recorder
  • Power type and voltage
  • Dry Batteries / 2 x 1.5 & 135 Volt
  • Loudspeaker
  • Permanent Magnet Dynamic (PDyn) Loudspeaker (moving coil) / Ø 2 inch = 5.1 cm
  • Material
  • Metal case
  • from Radiomuseum.org
  • Model: Nagra I - Kudelski SA; Cheseaux-sur-
  • Shape
  • Portable set > 8 inch (also usable without mains)
  • Dimensions (WHD)
  • 300 x 150 x 110 mm / 11.8 x 5.9 x 4.3 inch
  • Notes

  • The Nagra I is a self-contained clockwork-driven  tape recorder using 1/4 " magnetic tape in reels of 5", powered by two batteries of 2 x 1.5 V for the tube filaments and one of 135 V.

    During the year of 1951 Stefan Kudelski developed the Nagra I equipped with clockwork motor (Thorens) and low power electronic tubes. Kudelski sold some unities of the Nagra I for Radio Broadcast Stations and reporters with highly acclaimed success. At this time Nagra I was the most compact and best tape recorder for broadcasting reporters.

    In 1953, in a new facility, Nagra began the production of the Nagra II (a Nagra I with the option to have an external modulometer [a kind of a VU meter] in the sidewall and a tape available /time recording indicator in front panel. Very few (5) machines were produced without silk screen printing on the chassis indicating the tape path.   Later in the end of 1953  Nagra, employing  only 7 workers, improves the Nagra II  to the Nagra II b and, after this, in 1955, to the Nagra II c (a Nagra II with some improvements in electronics  and using the first Nagra printed circuit).

    In Nagra I and Nagra II tape transport is done using a mechanical spring (steel tape) motor (Thorens 144\F).  Electronics is hand wired within a very compact volume of 110 mm x 110 mm x 90 mm where the four tubes (pentodes), two DAF96 and two DL94, are assembled.

    The spring motor provides about 6 minutes of continuous recording and the battery discharge in about 5 hours of continuous use of electronics. The recorder has a mechanical indicator of available tape (or recording time) that is based on the number of revolutions available of spring tape of the motor. 

    With the help of the hand crank, the spring strength may be recharged. Rewind of tape is done manually by using a small key that can be plugged in a hole in the back of recorder.

  • Net weight (2.2 lb = 1 kg)
  • 4.5 kg / 9 lb 14.6 oz (9.912 lb)
  • Mentioned in
  • Clockwork-Driven Tape Recorders, by Roland Schellin
  • Author
  • Model page created by Moisés Piedade. See "Data change" for further contributors.

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