Miniature reel-to-reel tape recorders
By James Grahame
Roland Schellin's miniature tape recorder collection includes some stunning examples of 1950s and 1960s technology, including the world's first entirely solid state recorder - the Teltape. The most fascinating device of all is the tiny Minifon Mi51, which recorded on wire rather than magnetic tape:
The Minifon Mi51 was the world's first miniature magnetic recorder. The product line was built in Hanover, starting in 1951. Even the USA was not in a position to build such equipment at that point. The Minifon is a wire recorder that incorporates two miniature vacuum tubes . Three different batteries are necessary for operation: one for the motor, along with two to power the vacuum tube heater elements and anodes. The Minifon measured 17 x 11 x 3.5 cm - about the size of a wallet - and was intended to capture clandestine recordings. Corresponding accessories included a wrist-watch microphone and telephone adapter.