®Lorenz Dailygraph
1931 | 
Armour Model 50 -(Military Model:13-A-3-D)
1943 | 
Frederick Hart & Company - Model RD-11B/GNQ-1
1944 |
Radiotechnic Lab Model 20N-DS Device 13-A-3-C
1944
Additional Literature
1 2 3 | 
Magnecorder - Model SD-1
1946 | 
Webster-Chicago Electronic Memory Model 80-1
1947 |
Webster-Chicago Electronic Model 78-1 Wire Recorder
1947 | 
®Magnetic Corporation America Dictascriber 135
1948 | 
®Telemaster Telephone Answering Machine
1948 |
®Webster-Chicago Model 180-1 Wire Recorder “Electronic Memory”
1948
Additional Literature
1 2 3 | 
®Webster-Chicago Model 181-1B Wire Recorder
1950
Additional Literature
1 2 3 4 5 | 
®Webster-Chicago Model 228-1 Wire Recorder “Electronic Memory”
1951 |
®The Minifon “Special”
1953 | 
®The Minifon “P55”
1955 | |
 for a total recording time of one hour. Rewind of the wire is possible. Its separate electronic recording and playback amplifier features an automatic recording level circuit.'))
 - 1943</b></center><br>This classic recorder designed by Marvin Camras of Chicago’s Armour Research Foundation was the most successful of the military wire recorders and the first American machine to employ electronic amplifiers and 30 KHz AC bias. It also features two forward speeds, 5 and 2 feet per second (152 and 76 cm/s). The machine can rewind, has automatic end of wire stop, a recording time indicator, and a neon lamp recording level indicator.'))
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. A 1/2-pound spool of wire would record all communications over the interphone system for a period of 33 minutes'))
, a precision recording time indicator, a VU meter and 60 kHc AC bias. Its published specs are +/-2 dB 50-12,000 Hz, .2% flutter, 43 dB signal-to-noise ratio. Designer Russell J. Tinkham was an engineer with a sense of humor. \“SD\” stands for \“super duper\”!'))
 forward speed, a rewind speed of 10 feet per second (305 cm/s), R.M.A. standard 2-inch supply spool and neon recording level indicator. Built in a portable case, the 80-1 is Webster-Chicago’s earliest portable and the predecessor of the model 180'))
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