Stefan Kudelski – Recording Time

Last updated on March 18, 2021

Another aspect of tales about time, is the subject of audio recording, in essence capturing voices and sounds of past moments in time, for posterity. The same could be said of photography, or painting, or memoirs writing, all vying to capture the essence of an experience, a thought, a person, a place, in a medium that allows those moments to live on as long as they are preserved.

In the case of audio recording, there is a long line of technical inventions and advances from the late 19th century, from innovators like Thomas Edison. Various mediums were used to capture the sounds: wax cylinders, grooved flat circular shellac-based or polyvinyl discs, and eventually magnetic tape.

One of the great innovators in magnetic tape audio recording was Stefan Kudelski (1921 – 2013), the son of a Polish war refugee family that had escaped Nazi invasion in 1939, went to Romania, Hungary and finally France. When the Nazis invaded France, they moved again and settled in Switzerland. Stefan studied in Lausanne at the Swiss Federal Institute of Technology  where as a student, he designed and built his first tape recorder. The recorder was originally designed to contain instructions to drive a machine tool, but Kudelski realized that it was suitable to recording audio, and focused his efforts on this use for the ensuing years, eventually forming his own company.

Stefan Kudelski with the Nagra III (circa 1958)

Tape recording up to that point had been done using large tube-based audio recorders running on mains electricity. That was fine for sound-stage film recording, or studio music recording, but for recording live events outdoors, those large recorders were very problematic and cumbersome. Kudelski’s moment of genius was to design a portable recording machine that could run off batteries and be carried by a case and strap on the shoulder of the recordist, connected to a suitable microphone either hand-held (by a reporter for example) or at the end of a pole (for film recording).

Stefan was mainly an electronics expert, designing and building the circuitry to provide efficient and quality audio recording in an increasingly compact and rugged portable case. Eventually, Kudelski also designed the “time-code” circuitry (called “neopilot”) that allowed the audio recording on the magnetic tape, to be synchronized with the visual recording by the film camera.

He initially worked with people from other trades, including clock- and watchmakers rendered out of work by the aftermath of the second World War, to develop all the mechanical components needed to transport the tape in the machine, and allow all the complex and fine-tuned controls to work. In this sense, Kudelski’s work on the early portable tape recorders that bore the name “Nagra” (which came from the Polish expression “I record”), built upon long traditions of clockmaking and other complex mechanical mechanisms that had been developed in Switzerland for 200 years or more.

I was quite passionate about Stefan Kudelski and swiss Nagra audio recorders for many years, using them to make numerous audio recordings in my home. I collected different analog recorders, both mono and stereo, spanning the first couple of decades of Kudelski’s production (until he and his company inevitably turned to digital audio recording, which did not interest me as much as analog). I also acquired numerous pieces of documentation on the various models in the Kudelski line (sales and promotional literature, operating and service manuals). For many years, I amused myself in learning how these intricate and beautiful machines were made, both mechanically and electronically, and tried to educate myself on how to maintain and occasionally repair them.

Once my interests shifted to antique clocks and watches, my involvement with Nagra recorders became more dormant, and though I still have a few of the remaining machines in my collection on display, I have not used them for actual recordings for many years (preferring using more convenient – and affordable – digital recorders from American of Japanese companies instead). But the Nagra recorders, which are legendary in recording the vast majority of the audio for film and television worldwide, still are objects of devotion and admiration for me, and I felt it appropriate to describe some of their aspects on this site, to pay my respect to Stefan Kudelski and the many collaborators who helped him design and hand-craft these beautiful mechanical objects.

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