• Country
• United States of America (USA)

• Manufacturer / Brand
• Sears, Roebuck & Co.; Chicago (IL)

• Year
• 1941

• Category
• Broadcast Receiver - or past WW2 Tuner

• Radiomuseum.org ID
• 57030

• • Brand: Silvertone

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

• Number of Tubes
• 5

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

• Main principle
• Superheterodyne (common); ZF/IF 455 kHz

• Tuned circuits
• 6 AM circuit(s)

• Wave bands
• Broadcast only (MW).

• Power type and voltage
• Storage and/or dry batteries / 90 & 1.5 Volt

• Loudspeaker
• Permanent Magnet Dynamic (PDyn) Loudspeaker (moving coil)

• Power out
• 0.17 W (unknown quality)

• Material
• Wooden case

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

• Shape
• Tablemodel, with any shape - general.

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

• Notes

• 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.

   

• Price in first year of sale
• 23.95 USD

• External source of data
• Ernst Erb

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

• Circuit diagram reference
• Rider's Perpetual, Volume 13 = 1942 and before

• Mentioned in
• Collector's Guide to Antique Radios 4. Edition

• Literature/Schematics (1)
• Riders 13-101

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

• Other Models

• Here you find 5602 models, 3252 with images and 4311 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from Sears, Roebuck & Co.; Chicago (IL)