Model: Soundmirror BK-401 (BK401)

Antique radios, Old Time Radios

Soundmirror BK-401 (BK401)

Country: United States of America (USA) Manufacturer/Brand: Brush Development Co.; Cleveland, Ohio
Year: 1946 Type: Music/speech recorder and/or -player.
Tonspeichergerät im weiteren Sinn, also auch Kassettengerät, CD-Player, Tonbandmaschine, Video-Maschine etc. möglich.Recorder and/or Player Mod.-ID = 83632 previous | Result List | next | New search for Radios etc. Schematics etc.: 2 (for members) Principle AF (audio) amplification only, one, two or three stages etc.
Niederfrequenzverstärkung.
Meist als «Nachsatz» zu einem Empfänger verwendet, um das Tonsignal zu verstärken - z.B. für Lautsprecherwiedergabe statt Kopfhörer.Audio-Amplification
Details Tonbandgerät oder Apparat mit Tonbandgerät.Tape Recorder
Power type and voltage AC set plus voltage range.
/ = 2 different voltages
- = voltage from-to
* = «Special»
Apparareil à courant alternatif. Tensions mentionnées.
/ = 2 Spannungswahlen
- = von-bis
* = Fabrikwahl/«Spezial»
Trafo ist nicht immer mit Primär- undSekundärwicklungen versehen. Dadurch kann das Chassis ein gefährlichesPotential führen.Alternating Current supply (AC) / 110 Volt
Loudspeaker/pwr.out Permanent magnet type moving coil speaker (principle by Rice-Kellog, without field excitation coil).
Haut-parleur avec système dynamique à aimant permanent (sans bobine d`excitation).
Permanentdynamischer Lautsprecher, also (modernes) Tauchspulenprinzip mit Selbsterregung bzw. Permanentmagnet statt Magnetspule. Siehe «Radios von gestern» Seiten 329ff.Permanent Magnet Dynamic (PDyn) Loudspeaker (moving coil)
from Radiomuseum.org Model: Soundmirror BK-401 (BK401) Material Wooden case. Most radios have a wooden cabinet until the WW2. Caisse en bois.
Die meisten Heim-Rundfunkempfänger führen von Beginn an bis etwa Ende 60er Jahre Holz als Gehäuse. Auch frühe Reiseempfänger zeigen Holz (speziell in den 20er Jahren) oder Holz mit Stoffüberzug etc.Wooden case
Shape Tablemodel, with any shape - general.
Dimensions (WHD) 450 x 290 x 350 mm / 17.7 x 11.4 x 13.8 inch
Valves / Tubes 10: 6SJ7 (more for members)
Notes The Soundmirror BK-401 is the second magnetic tape recorder-reproducer of the Brush Development Company. The operator instructions are mainly done by typewriting. The recording tape is made of paper. 3 motor drive !

Features: 1/4" mono full-track reel-to-reel recorder/reproducer. 3", 5" and 7" EIA hub reels for 2-hour recording. 7 1/2 ips only. Reels made by 3M.

Designed primarily for home-recording purposes. recordings may be made either from a crystal microphone, supplied with the unit, or from a phonograph pickup or the detector stage of a radio. The recording medium is coated-paper tape, marketed under the name of Magnetic Ribbon. Difficulties with slit tilt are avoided in the Soundmirror by using the same head for both recording and playback; a separate head, spaced about 1 inch from the recording head, is employed for erasing. During recording or playback the medium is held against the recording and erasing heads by felt pressure pads, which are automatically withdrawn when the "stop" switch is depressed. Any previous recording on the medium is automatically erased at the time a recording is made. Level is monitored during the recording period by means of a magic eye tube.

This model was suggested by Ernst Erb.

Courtesy Chazz Avery

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Soundmirror BK-401 (BK401) (Brush Development Co.; Cleveland, Ohio)