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Majestic Gothic 307 Ch= 300 (300-A)

Majestic Gothic 307 Ch= 300 ; Grigsby-Grunow - (ID = 670770) Radio
 
Majestic Gothic 307 Ch= 300 ; Grigsby-Grunow - (ID = 670771) Radio
 
Majestic Gothic 307 Ch= 300 ; Grigsby-Grunow - (ID = 670772) Radio
 
Majestic Gothic 307 Ch= 300 ; Grigsby-Grunow - (ID = 671122) Radio
Majestic Gothic 307 Ch= 300 ; Grigsby-Grunow - (ID = 1244512) Radio Majestic Gothic 307 Ch= 300 ; Grigsby-Grunow - (ID = 933742) Radio
Majestic Gothic 307 Ch= 300 ; Grigsby-Grunow - (ID = 941664) Radio Majestic Gothic 307 Ch= 300 ; Grigsby-Grunow - (ID = 1130546) Radio
Majestic Gothic 307 Ch= 300 ; Grigsby-Grunow - (ID = 1244517) Radio Majestic Gothic 307 Ch= 300 ; Grigsby-Grunow - (ID = 1244521) Radio
Majestic Gothic 307 Ch= 300 ; Grigsby-Grunow - (ID = 1507163) Radio Majestic Gothic 307 Ch= 300 ; Grigsby-Grunow - (ID = 1556874) Radio
Majestic Gothic 307 Ch= 300 ; Grigsby-Grunow - (ID = 1556875) Radio
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Majestic Gothic 307 Ch= 300 ; Grigsby-Grunow - (ID = 1244512) Radio
Grigsby-Grunow -: Majestic Gothic 307 Ch= 300 [Radio] ID = 1244512 408x600
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For model Majestic Gothic 307 Ch= 300 (300-A), Grigsby-Grunow (-Hinds) Co. (Majestic pre 1933); Chicago (IL)
 
Paese:  USA (Stati Uniti d'America)
Produttore / Marca:  Grigsby-Grunow (-Hinds) Co. (Majestic pre 1933); Chicago (IL)
Anno: 1932 Categoria: Radio (o sintonizzatore del dopoguerra WW2)
Valvole 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
Principio generale Supereterodina con stadio RF; ZF/IF 175 kHz
N. di circuiti accordati 7 Circuiti Mod. Amp. (AM)
Gamme d'onda Solo onde medie (OM).
Particolarità
Tensioni di funzionamento Alimentazione a corrente alternata (CA) / 117 Volt
Altoparlante AP elettrodinamico (bobina mobile e bobina di eccitazione/di campo)
Potenza d'uscita
Radiomuseum.org Modello: Majestic Gothic 307 Ch= 300 - Grigsby-Grunow -Hinds Co.
Materiali Mobile in legno
Forma Console, con gambe d'appoggio basse (< 50%).
Annotazioni Introduced Sept. 1932. 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 and suppressing signals below a certain level between stations with an additional tube. Two legs of the Reactor 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.

Description in Rider's Majestic 3-19:
"This is a reactor with three windings on three legs respectively of the iron core. The windings on the two end legs are connected in series with the pilot lamp, while the winding on the center leg is connected in series with the plates of the RF, 1st Detector, and IF tubes. An electrolytic condenser is connected so as to shunt the center winding. If no station is tuned in, a relatively large plate current will flow through the center winding. This saturates the iron core so that the reactance of the two outer windings is quite low, and considerable current therefore flows through the pilot light. When a station is tuned in, it operates the G-4-S Automatic Volume Control tube so that an automatic bias voltage is built up across Resistor R-9. This bias voltage is, in turn, impressed upon the control grids of the RF, 1st Detector and IF tubes. When this bias is impressed on these amplifier tubes, the normal AVC action the pilot light is therefore reduced, causing the pilot light to dim."

Replacing of the unique "Spray Shield Tubes" is done by ordinary tubes plus installation of a tube shield.
Prezzo nel primo anno 89.50 $
Fonte esterna dei dati Ernst Erb
Fonte dei dati Radio Collector`s Guide 1921-1932
Riferimenti schemi Rider's Perpetual, Volume 3 = 1933 and before
Bibliografia The Radio Collector's Directory and Price Guide 1921 - 1965 (Rider's Changes 7-11)
Letteratura / Schemi (1) Pre-War Consoles


Elenco delle radio e altri apparecchi della Grigsby-Grunow (-Hinds) Co. (Majestic pre 1933); Chicago (IL)
In questo link sono elencati 200 modelli, di cui 118 con immagini e 156 con schemi.




  
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