Xtratone Plus‑Valve Unit Penton (1926)

Penton Engineering Co.; London

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  • Year
  • 1926 ?
  • Category
  • Radio module post 1925 (not a part, not a key)
  • Radiomuseum.org ID
  • 371179

 Technical Specifications

  • Number of Tubes
  • 2
  • Valves / Tubes
  • Wave bands
  • Broadcast (MW) and Long Wave.
  • Power type and voltage
  • Powered by external power supply or a main unit.
  • Loudspeaker
  • - - No sound reproduction output.
  • Material
  • Various materials
  • from Radiomuseum.org
  • Model: Xtratone Plus‑Valve Unit [Penton ] - Penton Engineering Co.; London
  • Shape
  • Miscellaneous shapes - described under notes.
  • Dimensions (WHD)
  • 3.5 x 4.25 x 0 inch / 89 x 108 x 0 mm
  • Notes

  • Xtratone Plus‑Valve Unit

    Compact plug‑in amplifier providing two stages of low‑frequency amplification without modification to existing receivers.

    • Plugs directly into the last valve‑holder of the receiver.
    • Two valves mount on staggered holders atop the cylindrical body.
    • Internal resistance‑capacity coupling inserted in the plate circuit of the last valve.
    • Extra H.T. terminal supplies the resistance‑coupled valve; a two‑way switch connects the grid circuit to L.T.
    • Dimensions (excluding valves): 4¼ in high × 3½ in diameter.
    • Compact design allows installation in most sets with minimal space.

    Performance
    Tests showed a marked increase in amplification with no audible distortion, provided the grid‑voltage swing of the last valve was moderate. Recommended for valves with long, straight characteristics left of the zero grid‑voltage line. Advertised as converting a one‑valve set into a two‑valve receiver, or a two‑valve into a three‑valve, and so on — “Speaks Volumes for Itself!”

    Materials
    Metal cylindrical body; ebonite top plate; brass fittings; glass valves.

    Price (1926)
    21 shillings (standard model)
    23 shillings 6 pence (external model with flex and plug adaptor).

    Reappearance under J. L. Gottlieb (Olympia, Sept 1927)
    In September 1927, the Xtratone Plus unit resurfaced — not under Penton, but exhibited by J. L. Gottlieb at the Olympia Wireless Exhibition.
    This occurred shortly before Penton Engineering’s financial collapse, and no formal record exists explaining how Gottlieb obtained or continued the design. The transfer mechanism remains historically unresolved, though the Olympia display confirms the unit’s continued presence in the market beyond Penton’s demise.

    Remarks
    An ingenious and compact solution for domestic radio users seeking greater loudspeaker volume and clarity. Represents Penton Engineering’s final phase of innovation before its 1927 bankruptcy and the uncertain continuation of its designs under Gottlieb.

  • Price in first year of sale
  • 1.05 £
  • Mentioned in
  • -- Original prospect or advert (Amateur Wireless, 11 Sept 1926, p. 330.)
  • Literature/Schematics (1)
  • -- Original prospect or advert (Radio Times, 5 Nov 1926, p. 301.)
  • Author
  • Model page created by Gary Cowans. See "Data change" for further contributors.

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