Nuvistor

The Nuvistor is a miniaturized special design of an electron tube.

It has a metal instead of a glass housing and a ceramic floor and is therefore less sensitive break. Substantially reducing the external dimensions enables direct loading on printed circuit boards. Due to the reduced internal spacing of the electrodes changed electrical data such as an increased slope and compared with other electron tubes very good RF characteristics result. Since Nuvistoren are made exclusively of ceramic and metal, they work even under extreme temperature conditions.

Your manner of production differed significantly from that of other electron tubes: As the construction did not provide for the possibility of evacuation of the flask, was the complete system assembly to the closure of the flask under high vacuum.

The first Nuvistoren of RCA ( 6CW4 ) came in 1959 on the market - due to its exceptionally good electrical properties at VHF and UHF frequencies, they were used in the U.S. primarily in television tuners, but also in oscilloscopes and some special applications (example: first amplifier stage of a image pickup tube, various RF amplifier and measuring devices) made ​​use of the fact its beneficial properties.

Particular level of awareness reached the Nuvistortriode 13CW4 in connection with the two famous Neumann U- 47 and U -48 condenser microphone for professional studio applications: for reasons of profitability was the production of the pre-amp VF14m - a steel tube pentode Telefunken - towards the end of the 1950s adjusted. To solve this problem, the Neumann company decided temporarily for the above-mentioned Nuvistor, the VF14m replaced after a few modifications in the circuit design, resulting in significant tonal changes. With the Nuvistor - Vorverstärkervariante the Neumann company could no longer continue the great market success of the U-47 microphone with the original VF14m preamp.

However, the Nuvistoren obtained no large and long-lasting meaning more - that was also due to the simultaneous development of the semiconductor devices, which completely displaced this tube type.

Examples of Nuvistor valves and tubes by RCA are:

  • 7586 - First available on the market triode.
  • 8056 - triode for low supply voltage.
  • 8058 - triode for UHF applications.
  • 7895 - 7586 with greater slope.
  • 6DS4 - Successor to the 6CW4.
  • 6DV4 - triode with medium slope, as UHF oscillator used. Housing sometimes gilded.
Georg Neumann
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