Arcadia Magnascopic Dial

Seyon (Brand), Noyes Bros (Sydney) Ltd. & Noyes Bros (Melbourne) Pty Ltd.

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  • Year
  • 1937 ?
  • Category
  • Broadcast Receiver - or past WW2 Tuner
  • Radiomuseum.org ID
  • 363164

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

 Technical Specifications

  • Number of Tubes
  • 5
  • Main principle
  • Superheterodyne (common); ZF/IF 125 kHz; 2 AF stage(s)
  • Tuned circuits
  • 6 AM circuit(s)
  • Wave bands
  • Broadcast, Long Wave and Short Wave.
  • Power type and voltage
  • Alternating Current supply (AC) / 200-250 Volt
  • Loudspeaker
  • Electro Magnetic Dynamic LS (moving-coil with field excitation coil)
  • Material
  • Wooden case
  • from Radiomuseum.org
  • Model: Arcadia [Magnascopic Dial] - Seyon Brand, Noyes Bros Sydney
  • Shape
  • Tablemodel, high profile (upright - NOT Cathedral nor decorative).
  • Dimensions (WHD)
  • 16 x 18 x 10.5 inch / 406 x 457 x 267 mm
  • Notes

  • Ferranti “Arcadia” Receiver with Magnascopic Dial

    Imported to Australia and distributed by Noyes Bros in 1937.

    The Ferranti Arcadia was a high-performance, five-valve superheterodyne receiver representing a significant advancement over the earlier model. It was designed with a focus on refined performance and user-friendly operation, incorporating several features considered advanced for its time.

    Technical Features:

    • Circuit Design: The circuit incorporated a heptode frequency changer and a variable-mu pentode Intermediate Frequency (IF) amplifier operating at a frequency of 125 kc/s. A double-diode triode served as the second detector, AVC rectifier, and first audio amplifier.
    • Variable Selectivity and Tone Control: A unique design allowed for variable selectivity by adjusting the coupling in the IF transformer. This control could reduce interference, particularly on distant stations. The set automatically returned to a high-selectivity setting when the tuning dial was moved.
    • Inter-station Noise Suppression: An integrated noise suppression circuit worked by switching the IF amplifier's AVC supply to the undelayed signal rectifier, effectively quieting the receiver between stations.
    • Magnascopic Dial: For precise tuning, especially on the shortwave band, the receiver featured a "Magnascopic" optical device. This magnified a portion of the 180-degree translucent tuning scale and projected it onto a ground glass screen, providing an effective scale length of over six feet and allowing for accurate, backlash-free tuning.
    • Audio and Loudspeaker: The moving-coil loudspeaker was modified with a free-suspension cone to enhance bass response, resulting in a full and smooth low-end. While the high-note response was adequate, it was intentionally limited to avoid accentuating local interference noises.
    • Aerial Circuit: The aerial tuning circuit was a well-designed band-pass filter that included an image rejector to minimize unwanted signals. It used mixed coupling for medium and long waves and inductive coupling for the shortwave range.
  • Mentioned in
  • -- Original prospect or advert (The Australasian Radio World Sep 1, 1937, Page 21)
  • Author
  • Model page created by Gary Cowans. See "Data change" for further contributors.

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