Telefunken T 40W

Telefunken T40W: A photography of the inner life Telefunken T40W: A photography of the closed device Telefunken T40W key: Labels of the amplifier stages, tubes, etc.
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The Telefunken broadcasting device Type 40W (year of manufacture 1929) is build aesthetically appealing. At that time, technology was comprehensible even for (educated) laymen. On the other hand, the operation was not very comfortable: The volume had to be adjusted by combining the antenna matching (the turn-switch on the left) and the feedback (turn-switch on the right). When the feedback was increased too much, the broadcasting reciever became an "jamming transmitter".

Telefunken 40W underside

The device looks good from below, too. It's built on a pressed paper sheet instead of a sheet chassis. Electrical connections are partially realized by rivet strip conductors. Not until the 1950s, that method was implemented again, leading to the printed circuit boards.