OTB Type B

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
  • 76601
    • 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 B - OTB Brand, Harding, Holland &
  • Shape
  • Miscellaneous shapes - described under notes.
  • Notes

  • Circular crystal receiver similar in appearance to Type A but incorporating additional refinements. Type B is fitted with special plug‑in terminals on the sides and an internal lightning arrester, allowing operation with the cover in place and without disconnection. The tuning dial is marked “O.T.B.” and “G.P.O. Reg 745,” with scale divisions and terminal markings for aerial, earth, and phones.

    Technical data:
    Single‑circuit crystal receiver with plug‑in terminals and internal lightning protection. Adjustable cat‑whisker detector. Terminals for aerial, earth, and phones.

    Circular turned Oak "powder-box" 5"dia., 2.5"high. A deluxe version in ivory with brass feet was also available (rare).

    Notes:
    Marketed as the deluxe version of the O.T.B. Crystal Set. Sold at 30 shillings plus 1 shilling for the B.B.C. stamp. Each set was B.B.C. stamped, guaranteed, and finished in selected wood. Sole selling agents: Harding, Holland & Fry Ltd., 27 Garlick Hill, London, E.C.4.

    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
  • 1.55 £
  • 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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