Click on the picture for the situation before restauration
Radioset, blocksystem, consisting of four interconected units
In brown oak cabinets with ebonite front, Bakelite knobs and brass coupling strips.
The set consists of a tuning unit with a fixed and a movable coil, a HF unit with 1 tube and 1 coil, a detector unit with 1 tube and a power amplifier with 2 tubes, probably all bright emitters. The remains of 2 Philips DII tubes were found inside the unit, so the probable valve line-up was Philips DII (HF unit), Philips DI (detector) and 2 x Philips DII (amplifier). The radio came with a set of original coils. All coils have a solid and a hollow pin. The coils look British, with a pin diameter of 4.8 mm and a center distance of 19 mm. One of the coupling transformers is from the German Bco (almost certainly not original), and the other is stamped DPM. There are no other marked parts.
The texts "Erres G RADIOFON" and "R.S. Stokvis & Zonen" are engraved on the HF unit. The other cabinets have the text "RADIOFON", with the exception of the last, the amplifier. An Erres G, made by Dutch firm N.S.F., was introduced in the Netherlands in 1923, but it does not look much like this unit. The only similarity is that it is also an HF module. The link with Dutch trade firm R.S. Stokvis & Zonen (using the brand name Erres) is still not clear.
History
The radio set comes from Finland, where it was left in a summer house in 1939 by a Fin who fled to Sweden at the outbreak of the Winter War between the Soviet Union and Finland, which began on November 30, 1939 and ended on March 23, 1940. After WWII, in 1949, the summer house was bought by a Finnish lady who found the radio there. A grandson eventually sought information about Erres and Stokvis and ended up on my website. In 2018 the set was given to me. It was shipped to the Netherlands in January 2019. With many thanks to the generous giver: Carl Fredrik Sandelin, Helsinki, Finland.
The radio was not made in Finland itself, because the abbreviations for long and short wave do not match the abbreviations (L and K) used on the tuning unit. In Finnish, the letters P (Pitka) and L (Lyhyt) would have been used.
The radio was the first commercial radio imported in Finland.
The first adverts for the radio appeared in the Finnish press on October 7, 1923. In the magazine Suomen Kuvalehti of February 1924, the modular system was first described, complete with a number of pictures, showing some possible combinations.
1-valve receiver 3-valve receiver (above) and 5-valve receiver


The units were imported by the Finnish company Hedengren in Helsinki and came from the Danish Radiofon factory in Copenhagen.

The director was E.F. Thestrup-Andersen in 1923; the owner was P. Utzon Buch. Both gentlemen visited a major industrial exhibition in Moscow in September 1923. Radiofon seems to have been a company that was not well known in Denmark itself, because it mainly produced for the foreign market. In the Danish newspaper Fyns Venstreblad, Odense, of November 4, 1924, it is written that "Radiofon, mainly known abroad" has concluded several agreements with the Soviet government in Moscow.
The receiver was also sold in Norway by Einar Rustad in Kristiania (Olso). In advertisements from 1923 and in a newspaper article in the same year an identical set was described.
Data Valves  
Serial number: none
Dimensions (hwd): 56 x 20,5 x 10,8 cm
Made in: 1923
Given to me in: 2018
Voltages: 4/80 volt
   

Click on a valve for more information

Circuit

What was broadcast in 1923?

 

Listen to "High Society" by King Oliver's Jazz Band, recorded in Chicago, June 24, 1923

The Radiofon tuner
With a fixed and a movable coil, an antenna connection, a series / parallel switch (L/K), a tuning capacitor and a connection for a frame antenna below.

The Erres G / Radiofon HF amplifier
With one tube, a fixed coil, a switch for switching off the module, a switch for polarizing the coils on the tuning unit. (in this way, coils having a different winding direction can also be used), a tuning capacitor and a rheostat for the filament current.

The Radiofon detector
With one tube, two clamps, where a grid leak resistance can be fitted (for slightly later tubes, not always necessary with bright emitters) and a rheostat for the filament current.

The amplifier
With two tubes and two rheostats for the flament current. Below, a binding post for a set of headphones.

This page was last edited on 14.04.2024