Colorama FB-72 Farm Radio

General Electric Co. (GE); Bridgeport CT, Syracuse NY

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  • Year
  • 1937 ?
  • Category
  • Broadcast Receiver - or past WW2 Tuner
  • Radiomuseum.org ID
  • 42073
    • Brand: Musaphonic

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

 Technical Specifications

  • Number of Tubes
  • 7
  • Main principle
  • Superheterodyne (common); ZF/IF 465 kHz; 3 AF stage(s)
  • Tuned circuits
  • 8 AM circuit(s)
  • Wave bands
  • Broadcast, Short Wave(s) and Police.
  • Power type and voltage
  • Storage and/or dry batteries / 45 & 2 & 2 & "C" 4.5 Volt
  • Loudspeaker
  • Permanent Magnet Dynamic (PDyn) Loudspeaker (moving coil) / Ø 8 inch = 20.3 cm
  • Material
  • Wooden case
  • from Radiomuseum.org
  • Model: Colorama FB-72 Farm Radio - General Electric Co. GE;
  • Shape
  • Tablemodel, Tombstone = decorative upright, not cathedral but can have rounded edges.
  • Notes

  • The General Electric models Colorama FB-72, FB-73, FB-76 and FB-77 are "Farm Radios" wiht a Push-Pull output and Pentagrid Converter. Sync. Vibrator for +B. First tap on storage battery is used as filament supply. FB-72 and FB-76 have also a C-Battery - see also for a Bias-Cell. All 4 models are sharing the Rider's schematic 8-37 through 8-40. They features the Colorama tuning indicator (see post 5 etc.). In this case here it is only a Neon lamp which glows more or less, depending on the plate current of the 1E5G which control grid is connected to the ACG circuit. No reactor. A green stained light bulb is a tuning indicator for silent tuning only. Other Colorama systems have 7 lamps. This was a novelty in 1936 for GE sets - the Magic Eye was just on the market but GE wanted first to have it's own gadget which was a problem to service men and the cost was over twice that of the tuning eye.

    These models have a Magnetic Phonograph Pick-up with impedance 18,00 ohms at 1000cycles. Band B (Broadcast) covers 540 - 1600 kc, the band C (Fishery, Police etc.) 11600 - 5800 kc, and band D (SW) 5.8 - 18 mc. The Electrical Power Output is 1 watt undistorted and 1.6 watts maximum for FB-73 and FB-77 (storage battery) or 1.3 / 2.2 for FB-72 and FB-76. We doubt this information a bit. Other way round?

    Stein "Cathedral & Tombstone Radios" lists 2 bands for this model.

  • External source of data
  • Ernst Erb
  • Circuit diagram reference
  • Rider's Perpetual, Volume 8 = 1937 and before

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