• Country
• United States of America (USA)

• Manufacturer / Brand
• National Company; Cambridge & Malden (MA)

• Year
• 1950 ??

• Category
• Radio module post 1925 (not a part, not a key)

• Radiomuseum.org ID
• 87471

• • alternative name: National Toy Co.
  • Brand: Thrillbox

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

• Number of Tubes
• 2

• Valves / Tubes
• 12AX7 12AX7

• Main principle
• Audio-Amplification

• Power type and voltage
• Powered by external power supply or a main unit.

• Loudspeaker
• - For headphones or amp.

• Material
• Metal case

• from Radiomuseum.org
• Model: Select-o-ject SOJ-3 - National Company; Cambridge &

• Shape
• Chassis only or for «building in»

• Notes
• audio frequency (80 - 9000 Hz) peak / notch filter matching the HRO-50 and similar receivers.

• Price in first year of sale
• 25.00 $

• Author
• Model page created by Martin Bösch. See "Data change" for further contributors.

• Other Models

• Here you find 445 models, 284 with images and 189 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from National Company; Cambridge & Malden (MA)