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Majestic 72 Ch= 70 - 7A Early

Majestic 72 Ch= 70 - 7A; Grigsby-Grunow - (ID = 2141971) Radio Majestic 72 Ch= 70 - 7A; Grigsby-Grunow - (ID = 2336373) Radio
Majestic 72 Ch= 70 - 7A; Grigsby-Grunow - (ID = 1496420) Radio Majestic 72 Ch= 70 - 7A; Grigsby-Grunow - (ID = 1480562) Radio
Majestic 72 Ch= 70 - 7A; Grigsby-Grunow - (ID = 1902170) Radio Majestic 72 Ch= 70 - 7A; Grigsby-Grunow - (ID = 1900781) Radio
Majestic 72 Ch= 70 - 7A; Grigsby-Grunow - (ID = 1497140) Radio Majestic 72 Ch= 70 - 7A; Grigsby-Grunow - (ID = 1497161) Radio
Majestic 72 Ch= 70 - 7A; Grigsby-Grunow - (ID = 1497181) Radio Majestic 72 Ch= 70 - 7A; Grigsby-Grunow - (ID = 1497150) Radio
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Majestic 72 Ch= 70 - 7A; Grigsby-Grunow - (ID = 2141971) Radio
Grigsby-Grunow -: Majestic 72 Ch= 70 - 7A [Radio] ID = 2141971 696x1020
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For model Majestic 72 Ch= 70 - 7A Early, Grigsby-Grunow (-Hinds) Co. (Majestic pre 1933); Chicago (IL):
This is the 1928 model 72. The 1929 model 72 uses the same chassis (ch=70)but differs in cabinet; and chassis and power supply electronics.
 
Country:  United States of America (USA)
Manufacturer / Brand:  Grigsby-Grunow (-Hinds) Co. (Majestic pre 1933); Chicago (IL)
Year: 1928 Category: Broadcast Receiver - or past WW2 Tuner
Valves / Tubes 8: UX226 UX226 UX226 UY227 UX226 UX171A UX171A UX280
Main principle Special principle (see notes); 3 AF stage(s)
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 72 Ch= 70 - 7A [Early] - Grigsby-Grunow -Hinds Co.
Material Wooden case
Shape Console, Highboy (legs > 50 %).
Notes

One dial (primary tuning control knob) This set has a push-pull output stage using two 171A power tubes. It is made of walnut with burl walnut front panels and came with a Majestic electric power unit and Majestic dynamic power speaker.
Model 72 can use the 7P6 or 7P3 power unit. See also Majestic model 72 with chassis 7-B.

This model here shows the loudspeaker below that radio chassis and the B shows the opposite. Maybe one could chose, maybe it is typical for the two versions - we don't know yet. On the speaker unit one can read: Majestic, Power Speaker, Model G1 Serial no. 300012 (not sure, hard to see), for use with model 71, 72, 80 (not sure). The chassis reads: Majestic 7, Electric Receiver Model 70 Serial no. 7A-, Grigsby-Grunow Company, Chicago USA. The cabinet reads: Majestic, Electric Receiver, Model 72, Grigsby-Grunow Company, Chicago USA. There is a hum control adjust for minimum hum in speaker.

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.

Price in first year of sale 210.25 $
External source of data Carlos Vázquez-Hancock
Mentioned in October 27, 1928 Radio Doings magazine advertisement page 30

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



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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