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Building A Tape Recorder In 1949

tape

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.

Recording off a reel-to-reel with a credit card reader

If you’ve got a few reel-to-reel recordings of 1940s radio, how do you transfer those to a digital medium? [Evan Long] and his dad used a credit card reader built for the iPhone to transfer a vintage [Art Kassel] recording from magnetic tape to the digital domain of .MP3s.

A few months ago, we saw what goes into these Square credit card readers. They’re just a magnetic tape head with a resistor an 1/8″ jack that plugs directly into the headphone jack of any iDevice. Because there’s no hardware limitation of what the Square credit card reader can do, [The Long boys] decided to back up some old reel-to-reel tapes with an iPod Touch.

[Evan] and his father needed to perform a few modifications to the credit card reader; the tape head pressed against the plastic case too tightly to allow feeding 70-year-old tape through the device. After bending a bit of metal the credit card reader was ready to record the dulcet tones of the Big Band era.

It’s a neat build, and anything that reuses proprietary hardware (however limited) is alright in our book. Nice job, guys.