• Paese
• USA (Stati Uniti d'America)

• Produttore / Marca
• Sparks-Withington Co., (Sparton); Jackson, Michigan

• Anno
• 1929/1930

• Categoria
• Radio (o sintonizzatore del dopoguerra WW2)

• Radiomuseum.org ID
• 58954

Clicca sulla miniatura dello schema per richiederlo come documento gratuito.

• Numero di tubi
• 9

• Valvole
• 485_Sparton 485_Sparton 485_Sparton 485_Sparton 485_Sparton 485_Sparton 482-B 482-B 280

• Principio generale
• A circuiti accordati (amplif. diretta) senza reazione

• N. di circuiti accordati
• 4 Circuiti Mod. Amp. (AM)

• Gamme d'onda
• Solo onde medie (OM).

• Tensioni di funzionamento
• Alimentazione a corrente alternata (CA) / 100-130 Volt

• Altoparlante
• AP elettrodinamico (bobina mobile e bobina di eccitazione/di campo)

• Materiali
• Mobile in legno

• Radiomuseum.org
• Modello: Sparton 931AC Equasonne - Sparks-Withington Co., Sparton

• Forma
• Console di qualsiasi tipo

• Annotazioni

• The Sparton 931 (AC) 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 the tubes of model 591: 6 x 485 Sparton, 2 x 482B and 80. We have shown before the tube: 484 484 484 484 484 484 182 182 280 which would make only sense if it is special Sparton tubes. 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."

• Prezzo nel primo anno
• 179.00 $

• Fonte esterna dei dati
• Ernst Erb

• Fonte dei dati
• Radio Collector`s Guide 1921-1932

• Riferimenti schemi
• Rider's Perpetual, Volume 1 = 1931/1934 (for 1919-1931)

• Bibliografia
• The Radio Collector's Directory and Price Guide 1921 - 1965

• Letteratura / Schemi (1)
• Radio Manufacturers of the 1920's, Vol. 3 (page 122)

• Letteratura / Schemi (2)
• Sparton Radio Service Manual (Sparton Manual 1, Bulletin 18-1, 2, Bulletin 6-3, 4)

• Altri modelli

• In questo link sono elencati 817 modelli, di cui 365 con immagini e 754 con schemi.
  Elenco delle radio e altri apparecchi della Sparks-Withington Co., (Sparton); Jackson, Michigan