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Mail-A-Voice BK-503

Mail-A-Voice BK-503; Brush Development Co (ID = 900900) R-Player
Mail-A-Voice BK-503; Brush Development Co (ID = 900069) R-Player Mail-A-Voice BK-503; Brush Development Co (ID = 900072) R-Player
Mail-A-Voice BK-503; Brush Development Co (ID = 900073) R-Player Mail-A-Voice BK-503; Brush Development Co (ID = 900075) R-Player
Mail-A-Voice BK-503; Brush Development Co (ID = 462139) R-Player Mail-A-Voice BK-503; Brush Development Co (ID = 900074) R-Player
Mail-A-Voice BK-503; Brush Development Co (ID = 900077) R-Player Mail-A-Voice BK-503; Brush Development Co (ID = 900080) R-Player
Mail-A-Voice BK-503; Brush Development Co (ID = 1247168) R-Player Mail-A-Voice BK-503; Brush Development Co (ID = 1247170) R-Player
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Mail-A-Voice BK-503; Brush Development Co (ID = 900069) R-Player
Brush Development Co: Mail-A-Voice BK-503 [R-Player] ID = 900069 480x640
Select picture or schematic to display from thumbnails on the right and click for download.
For model Mail-A-Voice BK-503, Brush Development Co.; Cleveland, Ohio:
Top/Front view
 
Country:  United States of America (USA)
Manufacturer / Brand:  Brush Development Co.; Cleveland, Ohio
alternative name
 
Brush Electronics
Year: 1948 ?? Type: Recorder and/or Player
Valves / Tubes 3: 6SL7GT 6SN7 6X5
Principle Audio-Amplification
Wave bands - without
Details Other Recorder/Player
Power type and voltage Alternating Current supply (AC) / 110 Volt
Loudspeaker - only for Earphone!
Power out
from Radiomuseum.org Model: Mail-A-Voice BK-503 - Brush Development Co.;
Material Metal case
Shape Tablemodel, with any shape - general.
Notes The model BK-503 Mail-A-Voice from "The Brush Development Company", represents an entirely different approach to the problem of storing information on a magnetic medium. The recording material in this case is in the form of a 9-inch disc, and the sound track is a spiral running from an inner diameter of 5 inches to the outer edge. The recording track has a width of 0.014 inch, and the pitch of the spiral is 0.025 inch. Despite this close spacing, no noticeable crosstalk can be detected. The powder-coated paper discs can be folded and mailed like an ordinary letter. No guide grooves are provided on the coated discs.

The turntable rotates 20 r.p.m., resulting in a total recording time of slightly over 3 min. This instrument deserves special mention because it presently represents the most simple and basically the most inexpensive mechanical and electrical design for a magnetic recorder that has been produced commercially. A single crystal headphone is used both as a recording microphone and as a playback earphone.
Collectors' prices  

Model page created by Ernst Erb. See "Data change" for further contributors.

All listed radios etc. from Brush Development Co.; Cleveland, Ohio
Here you find 38 models, 34 with images and 21 with schematics.


  
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