Magnetic Tape Recorder 731

• Country
• United States of America (USA)

• Manufacturer / Brand
• Ampro Corp.; Chicago (IL)

• Year
• 1951/1952

• Category
• Sound/Video Recorder and/or Player

• Radiomuseum.org ID
• 32593

• Picture
• Schematics

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

• Number of Tubes
• 4

• Valves / Tubes
• 12AX7 6AU6 6AQ5 6X4

• Main principle
• Audio-Amplification

• Wave bands
• - without

• Details
• Tape Recorder

• Power type and voltage
• Alternating Current supply (AC) / 105-120 Volt

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

• Power out
• 3 W (unknown quality)

• Material
• Leather / canvas / plastic - over other material

• from Radiomuseum.org
• Model: Magnetic Tape Recorder 731 - Ampro Corp.; Chicago IL

• Dimensions (WHD)
• 300 x 260 x 200 mm / 11.8 x 10.2 x 7.9 inch

• Notes

• ---

  The Model 731 from Ampro Corp in Chicago (IL) is a Magnetic Tape Recorder ans Playback Unit. The 12AX7 is selected. For mechanical unit service
  see also model 730 Photofact set 133, folder 4. The model 731 has an Ext. Speaker Jack besides the inbuilt speaker.

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  Este modelo tiene una sola velocidad (3 3/4), carretes max. 7", 2 cabezas grabación/reproducción, borrado por imán permanente monoaural y un sólo canal, un motor, respuesta a frecuencia: 50Hz-6kHz, relación señal/ruido 42 db.

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• Net weight (2.2 lb = 1 kg)
• 7 kg / 15 lb 6.7 oz (15.419 lb)

• Price in first year of sale
• 96,000.00 francs

• External source of data
• Ernst Erb

• Circuit diagram reference
• Rider's Perpetual, Volume 22, covering 1951

• Literature/Schematics (1)
• Photofact Folder, Howard W. SAMS (Date 5-52, set 166, folder 5)

• Other Models

• Here you find 16 models, 12 with images and 6 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
  All listed radios etc. from Ampro Corp.; Chicago (IL)