4-Valve Screen Grid Portable B4 Second cabinet design

Murphy Radio Ltd.; Welwyn Garden City

  • Year
  • 1932
  • Category
  • Broadcast Receiver - or past WW2 Tuner
  • Radiomuseum.org ID
  • 77942

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

 Technical Specifications

  • Number of Tubes
  • 4
  • Main principle
  • TRF with regeneration; 2 AF stage(s); Screengrid 1926-1935
  • Tuned circuits
  • 1 AM circuit(s)
  • Wave bands
  • Broadcast (MW) and Long Wave.
  • Power type and voltage
  • Storage and/or dry batteries
  • Loudspeaker
  • -Loudspeaker incorporated, but system not known.
  • Material
  • Wooden case
  • from Radiomuseum.org
  • Model: 4-Valve Screen Grid Portable B4 Second cabinet design - Murphy Radio Ltd.; Welwyn
  • Shape
  • Portable set > 8 inch (also usable without mains)
  • Dimensions (WHD)
  • 15 x 17 x 9 inch / 381 x 432 x 229 mm
  • Notes
  • 4-Valve Screen Grid Portable

    • Single Tuning Control
    • Completely Ganged Circuits Calibrated in Wavelengths
    • Fitted in beautiful Walnut Cabinet
    • No aerial or earth is required.
    • B.R.V.M.A. Valves.
    • 2 -volt, 23 AH Accumulator, mounted on an acid-proof rack.
    • 108-volt HT Battery, 12 mA. rating. Average HT consumption, 8-9 mA.
    • Gramophone Jack.
    • External Loudspeaker Jack.
    • External aerial and earth sockets.

    The circuit comprises a single-screen grid stage of HF amplification, reacting leaky grid detector, and two transformer-coupled LF stages.

    Excellent loudspeaker reproduction, giving very enjoyable music and particularly clear speech.

    Range and selectivity are equal to, if not better than, any other portable set on the market.

    The cabinet was redesigned in early 1932. No alterations were made to the chassis.  See B4 first cabinet design.

    Polished Walnut cabinet by R.D. Russell.

  • Price in first year of sale
  • 17.85 GB £

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Forum contributions about this model: Murphy Radio Ltd.;: 4-Valve Screen Grid Portable B4 Second cabinet design

Threads: 1 | Posts: 1

THE 1932 MURPHY PORTABLE.

Original Chassis to be Continued in a Redesigned Cabinet

When first introduced nearly two years ago the Murphy type B4 receiver at once established for itself a position in the front rank of portable sets of the better class. The performance in the matter of range and selectivity was exceptionally good, and the arrangement of the controls on the top of the cabinet with a ledge upon which to rest the hands when tuning was an idea that earned universal approval.

 

We are glad to note that this feature is retained in the 1932 edition of the B4 portable.
The only alteration to the cabinet takes the form of a new loudspeaker grille of bold and original design. No alterations have been made to the chassis, as the original screen grid H.F. - detector - 2 L.F. circuit gives a performance that is still more than adequate for present-day reception conditions. It is a tribute to the intrinsic soundness of the design that this performance is being repeated consistently in current sets. This was proved by a recent test on a receiver drawn from stock. Upwards of twenty-five reliable programs were available on the lower waveband after dark, while four or five mediumwave stations, including Brussels, Hilversum, and Langenburg, came through well in daylight. The efficiency on long waves is equally good, and the selectivity on both wave- ranges is exceptionally good, even for a set employing a frame aerial. The price of the Murphy portable in its latest form is fifteen guineas

Wireless world April 20, 1932, page 412

Gary Cowans, 27.Feb.22

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