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Majestic Ch= 300 Twin Speaker

Majestic Ch= 300 Twin Speaker; Grigsby-Grunow - (ID = 670767) Radio
 
Majestic Ch= 300 Twin Speaker; Grigsby-Grunow - (ID = 670768) Radio
 
Majestic Ch= 300 Twin Speaker; Grigsby-Grunow - (ID = 670769) Radio
 
Majestic Ch= 300 Twin Speaker; Grigsby-Grunow - (ID = 671121) Radio
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Majestic Ch= 300 Twin Speaker; Grigsby-Grunow - (ID = 670767) Radio
Select picture or schematic to display from thumbnails on the right and click for download.
 
Country:  United States of America (USA)
Manufacturer / Brand:  Grigsby-Grunow (-Hinds) Co. (Majestic pre 1933); Chicago (IL)
Year: 1932/1933 Category: Broadcast Receiver - or past WW2 Tuner
Valves / Tubes 11: G-58-S G-56 G-58-S G-58-S G-4-S G-57-S G-57-S G-58-S G-47 G-47 G-82
Main principle Superhet with RF-stage; ZF/IF 175 kHz
Tuned circuits 7 AM circuit(s)
Wave bands Broadcast only (MW).
Details
Power type and voltage Alternating Current supply (AC) / 117 Volt
Loudspeaker Electro Magnetic Dynamic LS (moving-coil with field excitation coil)
Power out
from Radiomuseum.org Model: Majestic Ch= 300 Twin Speaker - Grigsby-Grunow -Hinds Co.
Material Metal case
Shape Chassis only or for «building in»
Notes The series 300 models are fitted either with a large G-14-F speaker or have twin speaker G-19-B and G-19-C. Grigsby-Grunow uses here the first time their "Automatic Synchro-Silent Tuning", variing a tuning light by a reactor with 3 legs of iron core. Two legs are connected in series with the pilot light, while the winding on the center leg is connected in series with the plates of the RF First Detector, and IF tubes. An electrolytic condenser (C-5) shunts the center winding for not getting any AC if there are unbalances. They call the system also "Reactance Resonance Indicator". When a station is tuned in, an automatic bias voltage is built across Resistor R-9, causing the pilot light to dim.
External source of data Ernst Erb
Circuit diagram reference Rider's Perpetual, Volume 3 = 1933 and before
Mentioned in Rider's Changes 7-11


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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