• Year
  • 1930 ??
  • Category
  • Audio Amplifier or -mixer
  • Radiomuseum.org ID
  • 257257

Click on the schematic thumbnail to request the schematic as a free document.

 Technical Specifications

  • Number of Tubes
  • 3
  • Valves / Tubes
  • Main principle
  • Audio-Amplification
  • Wave bands
  • - without
  • Power type and voltage
  • Storage and/or dry batteries / 2 or 4 or 6 & 72 Volt
  • Loudspeaker
  • - - No sound reproduction output.
  • Material
  • Metal case
  • from Radiomuseum.org
  • Model: Note Filter 358 - MIM, Marconi International
  • Shape
  • Boatanchor (heavy military or commercial set >20 kg).
  • Notes
  • The note filter Type 358 consists of three stages of AF transformers with variable cores, the secondary of each transformer being tuned in each case to the required AF frequency range. It may be tuned to accept any "note" from approx. 800 to 1,200 cycles.

    The device is specifically designed for operation with receiver Type 352, and suitable for working with either 2, 4, or 6-volt valves, the anode voltage being of the order of 72 volts.

    A three-position switch determines the mode of operation. In mode "in", the note filter follows the AF valve of the 352 receiver. In the "off" position, filaments are disconnected and there is no through circuit to the headphones. Position "out" has the filaments equally disconnected, but a through circuit is arranged between the telephones and the receiver.

    Amplification and selectivity of the note filter can be controlled by means of a filament rheostat.

  • Mentioned in
  • - - Manufacturers Literature
  • Author
  • Model page created by Mark Hippenstiel. See "Data change" for further contributors.

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