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Majestic 71 Ch= 70-B Late

Majestic 71 Ch= 70-B; Grigsby-Grunow - (ID = 643736) Radio
 
Majestic 71 Ch= 70-B; Grigsby-Grunow - (ID = 1902681) Radio
 
Majestic 71 Ch= 70-B; Grigsby-Grunow - (ID = 1902682) Radio
 
Majestic 71 Ch= 70-B; Grigsby-Grunow - (ID = 1902683) Radio
 
Majestic 71 Ch= 70-B; Grigsby-Grunow - (ID = 1902684) Radio
 
Majestic 71 Ch= 70-B; Grigsby-Grunow - (ID = 1902685) Radio
 
Majestic 71 Ch= 70-B; Grigsby-Grunow - (ID = 1902686) Radio
 
Majestic 71 Ch= 70-B; Grigsby-Grunow - (ID = 1902687) Radio
Majestic 71 Ch= 70-B; Grigsby-Grunow - (ID = 1659846) Radio Majestic 71 Ch= 70-B; Grigsby-Grunow - (ID = 632415) Radio
Majestic 71 Ch= 70-B; Grigsby-Grunow - (ID = 1659848) Radio Majestic 71 Ch= 70-B; Grigsby-Grunow - (ID = 1883117) Radio
Majestic 71 Ch= 70-B; Grigsby-Grunow - (ID = 1900810) Radio
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Majestic 71 Ch= 70-B; Grigsby-Grunow - (ID = 1659846) Radio
Grigsby-Grunow -: Majestic 71 Ch= 70-B [Radio] ID = 1659846 791x1200
Select picture or schematic to display from thumbnails on the right and click for download.
For model Majestic 71 Ch= 70-B Late, Grigsby-Grunow (-Hinds) Co. (Majestic pre 1933); Chicago (IL):
Scanned from the Grigsby-Grunow Co. Folder "electric Radios" for Majestic.
 
Country:  United States of America (USA)
Manufacturer / Brand:  Grigsby-Grunow (-Hinds) Co. (Majestic pre 1933); Chicago (IL)
Year: 1928/1929 Category: Broadcast Receiver - or past WW2 Tuner
Valves / Tubes 8: UX226 UX226 UX226 UY227 UX226 UX171A UX171A UX280 or CX380
Main principle TRF without regeneration; Neutrodyne
Tuned circuits 4 AM circuit(s)
Wave bands Broadcast only (MW).
Details
Power type and voltage Alternating Current supply (AC) / 90-130 Volt
Loudspeaker Electro Magnetic Dynamic LS (moving-coil with field excitation coil)
Power out
from Radiomuseum.org Model: Majestic 71 Ch= 70-B [Late] - Grigsby-Grunow -Hinds Co.
Material Wooden case
Shape Console, Lowboy (legs < 50 %).
Notes

Push-pull af output stage; using the 7BP6 or 7BP3 power unit.

This radio is a cascade of 3 individual TRF stages, each with its own feedback coil forming a Wheatstone bridge acting as a Hazeltine neutralization for the triode (described as the RFL circuit in contemporary sources). The feedback polarity is reversed with respect to the signal polarity through the Cag Miller-capacitance, in effect neutralising the triode tendency to oscillate.

This is the late version of Majestic model 71 from 1929 and later. See also the early version from 1928 with quite a different housing and chassis version 7A. We have found a picture of this later version as a low boy but are not sure if there is also a high boy with chassis version 7B - and vice versa. The difference can be seen on the plate: There you find the chassis Majestic 7, model 70 in the version 7A. This set and the early version have a push-pull output stage using two 171 power tubes. The Majestic 71 is made of walnut with burl walnut front panels and came with a Majestic electric power unit and Majestic dynamic power speaker.

Price in first year of sale 137.50 $
External source of data Ernst Erb
Circuit diagram reference Rider's Perpetual, Volume 1 = 1931/1934 (for 1919-1931)
Literature/Schematics (1) Beitman Radio Diagrams, Vol. 01, 1926-1938 (Rider's Perpetual, Volume 2 = 1932 and before)
Literature/Schematics (2) The Grigsby-Grunow Co. Folder "Electric Radios" for Majestic.


All listed radios etc. from Grigsby-Grunow (-Hinds) Co. (Majestic pre 1933); Chicago (IL)
Here you find 200 models, 118 with images and 154 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.




  
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