Mail-A-Voice BK-503
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.
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alternative name
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Brush Electronics | ||||
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| Year: 1948 ?? | Type: Recorder and/or Player | ||||
| Valves / Tubes | 3: 6SL7GT 6SN7 6X5 |
| Principle | Audio-Amplification |
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| 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 | 2 Collector prices (for members Radiomuseum.org) |
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 35 models, 32 with images and 20 with schematics.
Collection of Robert Weaver (CDN)
Collection of Lukas Tschudi (CH)
