• Año
  • 1929/1930
perfect model
  • Categoría
  • Radio - o Sintonizador pasado WW2
  • Radiomuseum.org ID
  • 58957

Haga clic en la miniatura esquemática para solicitarlo como documento gratuito.

 Especificaciones técnicas

  • Numero de valvulas
  • 8
  • Principio principal
  • RFS sin reacción; 1 Etapas de AF
  • Número de circuitos sintonía
  • 4 Circuíto(s) AM
  • Gama de ondas
  • OM (onda media) solamente
  • Tensión de funcionamiento
  • Red: Corriente continua (CC, inglés = DC) / 115-125 Volt
  • Altavoz
  • Altavoz electrodinámico (bobina de campo)
  • Material
  • Madera
  • de Radiomuseum.org
  • Modelo: Sparton 931DC Equasonne - Sparks-Withington Co., Sparton
  • Forma
  • Consola en general
  • Anotaciones
  • The Sparton 931DC Witherington model has one dial (primary tuning control knob) and offers a push-pull audio amplifier. Tubes according to the "Quantity and Types of Tubes" by Sparks-Withington for season 1929/30 would be 6 x  485_Sparton and 2 x 483 as model 301DC, but we show tubes 484 and 182 mentioned in the schematic. It does not make sense: 182 is a rectifier - this is a DC set only and 182 must be a special Sparton tube. See the article here about different radio seasons.

    In "Radio Retailing" May 1933, page 47, "Tricks of the Trade" we can read for models Sparton 69-A, 79-A, 930AC, 931AC, 931DC, 301DC and 301AC: "Fourth section of band-pass selector, just preceding RF sometimes cannot be tuned to resonance with first three sections, producing weak reception and loss in selectivity. Give first, second and third selector trimmers 3 turns clockwise. This makes slightly less tuning capacity necessary for given frequency and fourth section selector can not be adjusted for resonance. Balance set in customary manner with oscillator and output meter and re-adjust kilocycle scale on dial by loosening it on shaft and re-setting."

  • Ext. procedencia de los datos
  • Ernst Erb
  • Referencia esquema
  • Rider's Perpetual, Volume 1 = 1931/1934 (for 1919-1931)

 Colecciones | Museos | Literatura