Building A Tape Recorder In 1949


After telling a few stories about how he built a tape recorder as a 16-year-old boy in post-war Germany, [Hans] was finally cajoled into retelling this story in a proper form, giving the Internet one more example of how clever old-school tinkerers could be.

In 1949, [Hans] was but a wee lad of 16 and having built a crystal and tube radio set at 13 and 14 respectively desperately wanted a tour of the local radio station in Hamburg. A kind engineer responded to a letter and a month after requesting a tour [Hans] and his friend found themselves being guided around a proper radio station. One of the most impressive pieces of technology at the time was a tape recorder, which the engineer demonstrated by recording and playing back the voices of [Hans] and his friend. This was the first time [Hans] had ever heard his voice played back and instantly knew he needed to build one of these for himself.

Technical details on the theory and operation of a tape recorder were sparse, but [Hans] managed to come up with an amplifier, tape transport mechanism, a recording and playback head, and homemade magnetic tape made from a reel of iron filings glued to a reel of 8mm film stock.

Testing the equipment, [Hans] and his friend found the device simply wouldn’t work; the homemade magnetic tape was simply too thick, and you couldn’t just go out and buy a reel of magnetic tape. Undeterred, they mailed BASF, the only manufacturer of magnetic tape, and after a month received a 1000m reel of tape.

With tape that worked, [Hans] set about improving his recorder with a tape transport mechanism built from a turntable and a new recording head. This time, his tape recorder worked. When word got around of this amazing machine that could record music, [Hans] was invited to record the local symphony and the speeches for a senior group.

The first commercial reel to reel recorders were released in Germany a little more than a year after [Hans] completed his project, making this one of the more impressive DIY projects we’ve seen.

19 thoughts on “Building A Tape Recorder In 1949

  1. My question: was 1000m the correct figure? How large is a 1000m reel of early magnetic tape, and how safe is it? Is it the kind that winds up like a spring and is ready to pop and sever heads, or is it more like the filmy tape of today? I can’t imagine appropriate plastics were ready at that time! Help me out, someone who was there!!

  2. I’m not sure why he couldn’t get his home made tape to work, but before celluloid audio tape there were wire recorders and metal “tape” recorders.
    Ages ago I saw a documentary from the BBC where a bloke was “editing” tape by cutting and splicing, the splice was sweat soldered joins!

    this one is good, tips on “splicing” with square knots!

    One thing to note is modern tape recorders don’t simply modulate the magnetic field across the tape, they use a bias oscillator

    1. Bah jesus haha, here we go…good one but goddamit lol…there’s no arduino here!

      Back on topic, I’ve got a couple old radios and a bunch of antique electronics at my dad’s…the old school people, they really hacked up things, like airboard soldering that looks like sh*t but it works; and I guess they’re more creative since there hasn’t been much fundamental breakthrus for awhile….I prefer clean PCB’s and small yet visible components though.

  3. That’s a nice story, in a time where there were just little bits of information, and almost no material to work with. That was Germany post-war, where almost everything was destroyed. Good to read!
    It’s good to see the same BASF spirit being in place today. The companies handing us samples are doing just the same. I know the majority of the projects are condemned to be failed projects that will end up forgotten somewhere, but a few will become something, and the successfull inventors will be grateful, and we will heard more good stories like this one.

    And please, we all are sick of Arduino jokes. It’s just something that someone says only to make noise, without anything to add.

    1. Yea I know, the build is amazing enough but that he did it in 1949 Germany is just mind blowing, people were still having a hard time getting food and a 16 year old kid builds the 1949 equivalent of an iPad from junk he could scrounge together, I’ed like to hear more of what this guy accomplished.

      1. I imagine in 1949 he had plenty of junk to rummage through in post war Germany. A whole country’s worth of junk in fact. What the 8th Air Force didn’t flatten the 3rd Army did.

        1. His point being that IG farben were the guys behind so much of the technical aspect of the horrors of the german war machines, and the holocaust.
          So that ‘spirit’ would be making bombs and poisoned gas. Which some people don’t think are ‘good spirit’. Odd eh.

  4. Tim Hunkin demonstrated audio recording with rust powder on cellophane tape or “sticky tape” as they call it in the UK.

    Would love it if someone would do a Kickstarter to buy the original film prints of “The Secret Life of Machines” to do a good video transfer for DVD and Blu-Ray, especially since all video copies of “The Car” episode available to mere mortals are buggered, even on the DVD release.

  5. Some attic hacking with little heat other than that humongous iron. After reading the wiki article I remembered hearing on some radio program about early stereo experiments. Then you heard the Berlin Philharmonic in stereo on tape with Allied bombing in the distance! Some were allowed to play while war raged on.

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