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Majestic Ch= 180

Majestic Ch= 180; Grigsby-Grunow - (ID = 244694) Radio
Majestic Ch= 180; Grigsby-Grunow - (ID = 674740) Radio
Majestic Ch= 180; Grigsby-Grunow - (ID = 674741) Radio
Majestic Ch= 180; Grigsby-Grunow - (ID = 674742) Radio
Majestic Ch= 180; Grigsby-Grunow - (ID = 674747) Radio
Majestic Ch= 180; Grigsby-Grunow - (ID = 676635) Radio
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Majestic Ch= 180; Grigsby-Grunow - (ID = 244694) Radio
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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 9: 27 27 27 27 27 50 50 81 81
Main principle TRF without regeneration; 3 AF stage(s); Neutrodyne
Tuned circuits 4 AM circuit(s)
Wave bands Broadcast only (MW).
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 Model: Majestic Ch= 180 - Grigsby-Grunow -Hinds Co.
Material Metal case
Shape Chassis only or for «building in»

Push-pull af output stage; using the 8P6 or 8P3 power unit; chassis for Majestic model 181.

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.

The antenna circuit has a separate tuning coil, to be readjusted with each tuned frequency.

The tuning scale is graduated with 2 scales: One in frequency from 550 to 1500 kHz and the other as a linear scale from 0 to 100. 

LF coupling between stages is done by transformers - Push-pull output.

The unit contains a separate 8P6 or 8P3 power supply unit with individual transformers for the filaments and the 425 Volt anode supply. A current regulator is included in the primary circuit of the power transformers to compensate for mains voltage changes between 90 and 130 Volt AC.

External source of data Ernst Erb
Circuit diagram reference Rider's Perpetual, Volume 1 = 1931/1934 (for 1919-1931)
Literature/Schematics (1) Rider's Perpetual, Volume 2 = 1932 and before

All listed radios etc. from Grigsby-Grunow (-Hinds) Co. (Majestic pre 1933); Chicago (IL)
Here you find 200 models, 118 with images and 156 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.