• Country
• United States of America (USA)

• Manufacturer / Brand
• DeForest Radio Telephone & Telegraph Co. (De Forest); New York

• Year
• 1922

• Category
• Audio Amplifier or -mixer

• Radiomuseum.org ID
• 37099

• • alternative name: Lee De Forest Mfg.

• Number of Tubes
• 2

• Valves / Tubes
• UV201 UV201

• Main principle
• Audio-Amplification; 2 AF stage(s)

• Wave bands
• - without

• Power type and voltage
• Storage and/or dry batteries

• Loudspeaker
• - This model requires external speaker(s).

• Material
• Wooden case

• from Radiomuseum.org
• Model: Two-Stage A. F. Amplifier MP-400 - DeForest Radio Telephone &

• Shape
• Tablemodel, Box - most often with Lid (NOT slant panel).

• Notes
• The De Forest Radio Telephone & Telegraph Co. Combination Set MP-400 consisted of 2-MP-200 Single Stage Audio Amplifiers.

• External source of data
• Ernst Erb

• Source of data
• Radio Collector`s Guide 1921-1932

• Literature/Schematics (4)
• Deforest Radio Equipment Catalog H page 13

• Other Models

• Here you find 158 models, 133 with images and 16 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from DeForest Radio Telephone & Telegraph Co. (De Forest); New York