• Pays
• Etats-Unis

• Fabricant / Marque
• Grigsby-Grunow (-Hinds) Co. (Majestic pre 1933); Chicago (IL)

• Année
• 1932

• Catégorie
• Radio - ou tuner d'après la guerre 1939-45

• Radiomuseum.org ID
• 43628

Cliquez sur la vignette du schéma pour le demander en tant que document gratuit.

• No. de tubes
• 11

• Lampes / Tubes
• 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

• Principe général
• Super hétérodyne avec étage HF; FI/IF 175 kHz

• Circuits accordés
• 7 Circuits MA (AM)

• Gammes d'ondes
• PO uniquement

• Tension / type courant
• Alimentation Courant Alternatif (CA) / 117 Volt

• Haut-parleur
• HP dynamique à électro-aimant (électrodynamique)

• Matière
• Boitier en bois

• De Radiomuseum.org
• Modèle: Majestic Gothic 307 Ch= 300 - Grigsby-Grunow -Hinds Co.

• Forme
• Console avec pieds bas < 50% de la hauteur

• Remarques
• 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.

• Prix de mise sur le marché
• 89.50 $

• Source extérieure
• Ernst Erb

• Source
• Radio Collector`s Guide 1921-1932

• Source du schéma
• Rider's Perpetual, Volume 3 = 1933 and before

• Littérature
• The Radio Collector's Directory and Price Guide 1921 - 1965 (Rider's Changes 7-11)

• Schémathèque (1)
• Pre-War Consoles

• D'autres Modèles

• Vous pourrez trouver sous ce lien 201 modèles d'appareils, 122 avec des images et 157 avec des schémas.
  Tous les appareils de Grigsby-Grunow (-Hinds) Co. (Majestic pre 1933); Chicago (IL)