Ampro 731
Ampro
USA
Tape Deck Details
Number of Motors
Number of Heads
2
Head Configuration
Full-track-mono
Wow & Flutter
1%
Signal-to-Noise [dB]
42
Dimensions [mm]
300 x 260 x 200
Weight [kg]
7
Year built
1952 - 1955
Head Composition
Permalloy
Equalization
Frequency Response
50Hz - 6kHz
Speed
3¾
Max Reel [inch]
7
Tracks
1/2 Rec/PB
Price
User
Consumer
Additional Information
The Ampro 731 was an early-1950s AC-operated magnetic tape recorder and playback unit from Ampro Corp. of Chicago. It used 4 tubes, ran on 117 V AC, and produced about 3 W output through a built-in permanent-magnet speaker.
Technical overview
Format: reel-to-reel magnetic tape recorder/playback unit.
Tape: 1/4-inch tape with dual-track recording, giving longer play time per reel.
Speed: 3 3/4 ips recording/playback speed is the documented standard for the model family.
Power: AC mains, 105–120 V / 117 V, 60 Hz.
Amplification: tube-based audio section with 4 tubes, including a 12AX7 and a corrected 6AQ5 reference in the service notes.
Output: built-in speaker plus an external speaker jack.
Physical data
Dimensions: about 300 x 260 x 200 mm.
Weight: about 7 kg.
What it was for
The 731 was aimed at home users who wanted to record from a microphone or from radio/phonograph sources, and it was marketed as a practical consumer tape recorder rather than a professional deck.
Its 3 3/4 ips speed and dual-track format fit the early home-recording era, where ease of use and longer recording time mattered more than wideband hi-fi performance.