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One circuit TRF receiver with feedback
Primary receiver. The circuit is very similar to that of a NSF O40 made in 1923.
Sloping black ebonite control panel and oak cabinet. Classic model in the shape of a lectern.
Sockets for antenna and earth are situated at the top of the control panel, left and right of the two valves. Below the valves, a double coil holder for swinging coil tuning, a rheostat and a tuning knob with fine tuning. The sockets on the left are used for plate and filament voltages; the sockets on the right are for the headphone(s).
The radio was adapted for use with 1 volt valves. Batteries for filament and plate voltages were placed inside the cabinet, but this was not the way the radio was intended to function. The design is based on 4 volt tubes with a rechargeable lead acid battery for the filament and a 50 volts battery for the plate voltage.
The tube set is unknown. Presumably two A406s.
Data Valves Circuit  
Serial number: none
Dimensions (whd): 37  23,5  21,5 cm
Made in: 1925
Purchased in: 2011
Click on a valve for more information. Click on the circuit to enlarge.

What was broadcast in 1925?

 

Listen to "Rose Marie" played by the Belgian-Dutch formation "The Excellos Five",  Louis de Vries (tp), Henri van den Bossche (tb), Alphonse van Asbroek (cl, s), Joop de Leur (p), Bob Kierberg (dr, ld), recorded in Berlin, December 1925

The receiver before restoration
The receiver was made with rectangular wire. It was adapted for use with 1 volt valves with a side connection. By doing this, the batteries could be placed inside the cabinet. A small battery for the grid bias voltage was placed near the Habana transformer (it was already removed before taking this picture).
The receiver after restoration
The batteries were removed, the telephone condenser was repaired, two missing connections were added and the grid leak resistor was replaced.

Deze pagina is voor het laatst bijgewerkt op zaterdag 27 april 2019