TRF receiver

Four-valve AC receiver with a built-in loudspeaker. Just like the earlier Erres KY107 (1930-1931) it was called "Singer on the wall", or, in the French speaking part of Belgium, "Le Chanteur au Mur".

   Otto van Tussenbroek

Rigid "Haagse Stijl" design by Otto van Tussenbroek (1882-1957).
The cabinet is made of massive oak, decorated with two semi-circular strips made of coromandel wood and with two round openings sealed with brown speaker cloth in the sides. The front, with brown speaker cloth, is made of black crackle painted aluminium (upper part) and steel (lower part).
The radio was also exported, i.a. to Belgium. In that case the brand name "Stokvis" was used. R.S. Stokvis Radio was part of R.S. Stokvis et Fils, 15-19 Avenue de Dixmude, Brussels.
There are some differences between the Erres version and the Stokvis version. In this export model, a hatch is fitted in the underside of the power supply block, behind which the mains voltage of the device can be changed by means of metal connecting strips. The Stokvis radio therefore does not have a mains voltage tag. Furthermore, in the Stokvis receiver, the capacitor block was turned around, with the connections to the rear, and the resistor panel was also moved to the rear of the power supply block. The Stokvis radio does not have a Philips license sticker but a Belgian SBR-SEM license sticker.
The rear panel consists of three parts: a metal part with the word "Erres" or "Stokvis" that covers the power supply section, a silver-coloured cardboard part with punched-out slotted openings, which covers the middle compartment and a metal part at the bottom with the word "Radio".
The knobs from left to right: primary tuning, feedback, secondary tuning, wave length slide switch (down: medium wave, 200-600 meters and up: long wave, 1000-2000 meters.). Both scales (0-100) are illuminated by a bicycle lamp. (6 V, 0,3 A).
Made by Van der Heem & Bloemsma in The Hague. Date stamp on the loudspeaker: September 1st, 1931. Date stamp on the loudspeaker transformer of the  Stokvis receiverl: July 16, 1931. The Stokvis radio also has a Belgian licence label.
The chassis has a connection for a gramophone as well as the earth and antenna sockets. The Philips electrodynamic loudspeaker 2044 is connected to the chassis with a connector plug, so an external speaker can be used as well.
In 1932 the radio was also released by Lindeteves-Stokvis in the former Dutch East Indies. This radio was altered for shortwave reception (20-200 meters). In that model the slide switch has 3 positions. Up: 14-35 meters, down: 30-80 meters and mid-position: 70-200 meters. Valves: E428, E462, C453 and 1823. In 1933 the "Deluxe" version was introduced with extended short-wave (12-200 meters) and with a Baker electrodynamic loudspeaker.
The original price of the Dutch receiver was f 175,-; in Belgium the receiver cost BFr 3100,-. The version for the East-Indies cost f 240,-; the price of the Deluxe version was f 250,-.
On the left, an advertisement for the Belgian version of the KY108 in newspaper "Le Soir" October 15, 1931. They seem to have used a picture of the earlier KY107.
Data Valves
Serial number: 83745 / 81074 (Stokvis)
Production: ± 700
Dimensions (h x w x d): 49 × 37.5 × 18.5 cm
Made in: 1931
Purchased in: 2013 / 2019 (Stokvis)
Voltage: 220 Volts ~
Weight: 10.6 kg
Click on a valve for more information
Original circuit Restoration report
Redrawn circuit Article (in Dutch)
User manual KY108 User manual for the KY108 used in the tropics

What was broadcast in 1931?


Listen to "Ich bin ja heut' so glücklich" played by the Amsterdam Friedmanns Band, recorded during a competition for amateur jazz orchestras in the Bellevue building in Amsterdam, organized by magazine "Het leven" in 1931

Rear view of the Erres KY108 and the Stokvis KY108

Back and side view of the Erres KY108
Hatch in the power supply section Setting strips for the mains voltage Settings for the mains voltage

Bottom view of the chassis Top view of the power section

Picture in an Erres leaflet, 1931 Advertisement for the former Dutch East Indies version of the KY108 in Sumatra Post, Saturday, October 14, 1933
An Erres KY108 made for the former Dutch East Indies, photographed by Prayudi Wibowo in a museum in Djokjakarta, Indonesia.
The radio was owned by the Indonesian national hero, Ki Hajar Dewantara, writer of the manifesto "Als ik een Nederlander was" ("If I were a Dutchman"), written in 1913, a vehement protest against the plans of the Dutch colonial rulers to force the Indonesian population to pay for the celebration of 100 years of independence from French occupation of the Netherlands.
The pictures were made in the museum dedicated to the writer.
The back panel and wave length slide switch seem to have been sealed with red sealing-wax by the Japanese occupiers.

his page was last edited on 18.09.2020