OTB Type A

OTB (Brand), Harding, Holland & Fry Ltd.; London

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  • Year
  • 1923
  • Category
  • Detector-Radio (Crystal or diode, without tubes/transistors)
  • Radiomuseum.org ID
  • 76224
    • Brand: OTB (O.T.B.)

 Technical Specifications

  • Main principle
  • Crystal or Solid State Detector
  • Tuned circuits
  • 1 AM circuit(s)
  • Wave bands
  • Broadcast only (MW).
  • Power type and voltage
  • No Power needed
  • Loudspeaker
  • - For headphones or amp.
  • Material
  • Wooden case
  • from Radiomuseum.org
  • Model: OTB Type A - OTB Brand, Harding, Holland &
  • Shape
  • Miscellaneous shapes - described under notes.
  • Dimensions (WHD)
  • 0 x 2.25 x 0 inch / 0 x 57 x 0 mm
  • Notes

  • Compact crystal detector receiver housed in a circular wooden cabinet stamped with the B.B.C. mark of approval. The front panel carries the tuning dial and terminals for aerial, earth, and headphones. Type A is fitted with outside ordinary nickel‑plated terminals and omits the internal lightning arrester found on the companion model. The set was supplied complete and guaranteed, with each unit B.B.C. stamped and finished in selected wood.

    Technical data:
    Single‑circuit crystal receiver using a fixed aerial coupling and adjustable cat‑whisker detector. Terminals for aerial, earth, and phones.

    Turned Mahogany lidded box, 5"dia.; BBC/PMG stamp, GPO No.745. 

    Notes:
    Advertised as “Absolutely the Finest on the Market.” Sold at 25 shillings plus 1 shilling for the B.B.C. stamp. Distributed wholesale and through retailers by Harding, Holland & Fry Ltd., 27 Garlick Hill, London, E.C.4.

    See also Type B  incorporating additional refinements.

    Correction:
    Two period advertisements for the O.T.B. Crystal Set, distributed by Harding, Holland & Fry Ltd., London, present conflicting descriptions of the Type A and Type B models. The earlier advert (likely 1923) mistakenly reversed the technical details. The later advert clarifies the correct specifications:

    Model Description Price Features
    Type A Basic version 25/‑ + 1/‑ BBC stamp Ordinary outside nickel‑plated terminals; no lightning arrester
    Type B Deluxe version (illustrated) 30/‑ + 1/‑ BBC stamp Special plug‑in terminals on sides; internal lightning arrester; operable with cover on, no disconnection required
  • Price in first year of sale
  • 1.30 £
  • Mentioned in
  • -- Original prospect or advert (The Radio Times, 28 Dec 1923, p. 34.)
  • Literature/Schematics (1)
  • -- Original prospect or advert (Wireless Weekly Jun 30, 1924, p.267.)

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The model OTB is part of the collections of the following members.

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