500

Centrum-Radio, Gylling & Co.; Stockholm

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  • Year
  • 1958 ?
  • Category
  • Car Radio, perhaps also + sound player/recorder
  • Radiomuseum.org ID
  • 353179
    • Brand: Gylling

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

 Technical Specifications

  • Number of Tubes
  • 4
  • Number of Transistors
  • 2
  • Main principle
  • Superheterodyne (common); ZF/IF 450 kHz
  • Tuned circuits
  • 7 AM circuit(s)
  • Wave bands
  • Broadcast (MW) and Long Wave.
  • Power type and voltage
  • Storage Battery for all (e.g. for car radios and amateur radios) / 6 or 12 Volt
  • Loudspeaker
  • - This model requires external speaker(s).
  • Material
  • Metal case
  • from Radiomuseum.org
  • Model: 500 - Centrum-Radio, Gylling & Co.;
  • Shape
  • Chassis only or for «building in»
  • Notes

  • The "Centrum 500" is a car radio designed and built circa 1958 by Gylling & Co. in Stockholm, Sweden. It is the successor of the Centrum 100 from around 1952. 

    The 500 is a quirky design. It is MW and LW only. FM was taking over in Europe, but not popular in Sweden. 

    The 500 could operate on 6 or 12 V and plus or minus ground. It is a hybrid design with four tubes and two transistors. The tubes operate on 6.3 V (filament) and 12 V (anode). The ECH 83 is the mixer and local oscillator. The EF 97 pentode is the first 450 kHz IF. The EBF 83 is the second IF and demodulator. The first audio stage is a cathode follower connected as a triode, EF 98.  Audio output is a OC604spez germanium transistor (driver), and a 2N242 germanium transistor is the approximate 2 W output transistor. 

    To operate 12 V tubes on 6 V, the 6 V supply is connected in series with a set of button cell batteries raising the anode supply to 12 V.  When the radio is switched off, the car 6 V battery charges the button cells. 6/12 V change over is by a plug in small PCB where the four 1.5 V  cells  are mounted. 

    The build quality was poor and a typical last effort from an already struggling manufacturer.
     

  • Literature/Schematics (1)
  • -- Schematic
  • Author
  • Model page created by David Erali. See "Data change" for further contributors.

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