• Pays
• Etats-Unis

• Fabricant / Marque
• Sears, Roebuck & Co.; Chicago (IL)

• Année
• 1941

• Catégorie
• Radio - ou tuner d'après la guerre 1939-45

• Radiomuseum.org ID
• 57030

• • Brand: Silvertone

Cliquez sur la vignette du schéma pour le demander en tant que document gratuit.

• No. de tubes
• 5

• Lampes / Tubes
• 1A7GT 1P5GT 1P5GT 1H5GT 1A5GT

• Principe général
• Super hétérodyne (en général); FI/IF 455 kHz

• Circuits accordés
• 6 Circuits MA (AM)

• Gammes d'ondes
• PO uniquement

• Tension / type courant
• Piles (rechargeables ou/et sèches) / 90 & 1.5 Volt

• Haut-parleur
• HP dynamique à aimant permanent + bobine mobile

• Puissance de sortie
• 0.17 W (qualité inconnue)

• Matière
• Boitier en bois

• De Radiomuseum.org
• Modèle: Silvertone 7104 Ch= 101.644 - Sears, Roebuck & Co.; Chicago

• Forme
• Modèle de table générique

• Dimensions (LHP)
• 15 x 11.75 x 11 inch / 381 x 298 x 279 mm

• Remarques

• Sears-Roebuck's Silvertone model 7104 was priced at $23.95 including an A-B battery pack.  It used the "Stratobeam" circuit, Sears description for its inductor tuning. 

  A red "Battery Economizer" slide switch on the front panel selected a connection for a new battery (left side) or a partly-worn battery. In the "new" battery position, that switch connected two resistors in the "A" and "B" battery feeds which reduced the voltage and current. Those resistors were shorted out when the partly-worn battery position was selected. The resistors were 0.72 ohm for the "A" side and 2700 ohms for the "B" side.  The lower voltages caused a reduction in nominal current draw from a new battery, enhancing battery life when listening at reduced volume or to a stronger local station.

  The dual IF tubes made for greater sensitivity, useful for farms in isolated sections of the country.  

  The use of the 1A5GT for audio output required only 50 mA for its filament but also limited the undistorted audio power to 85 milliwatts, as noted on the Rider schematic.  The simple antenna terminal allowed then use of a trailing wire or a proper external antenna.  An antenna trimmer located adjacent to the antenna connection terminal allowed for the end user to max the sensitivity for a given antenna.

   

• Prix de mise sur le marché
• 23.95 USD

• Source extérieure
• Ernst Erb

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

• Source du schéma
• Rider's Perpetual, Volume 13 = 1942 and before

• Littérature
• Collector's Guide to Antique Radios 4. Edition

• Schémathèque (1)
• Riders 13-101

• Schémathèque (2)
• -- Original-techn. papers. ("The Sears-Roebuck Farm Set; Silvertone 7104" , RPost, in "The Spectrum Monitor", Apr 2026, p66-71)

• D'autres Modèles

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  Tous les appareils de Sears, Roebuck & Co.; Chicago (IL)