If you think of old recording technology, you probably think of magnetic tape, either in some kind of cassette or, maybe, on reels. But there’s an even older technology that recorded voice on hair-thin stainless steel wire and [Mr. Carlson] happened upon a recorded reel of wire. Can he extract the audio from it? Of course! You can see and hear the results in the video below.
It didn’t hurt that he had several junk wire recorders handy, although he thought none were working. It was still a good place to start since the heads and the feed are unusual to wire recorders. Since the recorder needed a little work, we also got a nice teardown of that old device. The machine was missing belts, but some rubber bands filled in for a short-term fix.
The tape head has to move to keep the wire spooled properly, and even with no audio, it is fun to watch the mechanism spin both reels and move up and down. But after probing the internal pieces, it turns out there actually was some audio, it just wasn’t making it to the speakers.
The audio was noisy and not the best reproduction, but not bad for a broken recorder that is probably at least 80 years old. We hope he takes the time to fully fix the old beast later, but for now, he did manage to hear what was “on the wire,” even though that has a totally different meaning than it usually does.
It is difficult to recover wire recordings, just as it will be difficult to read modern media one day. If you want to dive deep into the technology, we can help with that, too.
Hogan’s Heroes TV series featured custom build wire recorder/player that POW used. This is the only reason I knew of it. The one used in the show is fake and audio is added to the film during editing.
We had one of those when I was a kid, some 60 years ago that my Dad had picked up during the war. The fidelity was surprisingly good on fresh recordings, but if the spools sat for a few months the crosstalk was quite noticeable. One of the tubes finally gave out, and the unit was eventually junked when I was at university
picked up a wire recorder sitting on a shelf at a scrap yard, with 2 reels of wire, $10
there are always bit and pieces, oddities, that the crews will set aside, though this does highlight, just what gets thrown into the shreders to be rendered for its intrinsic value
Carlson says it’s stainless, but I wonder what the alloy really is. Many stainless steels aren’t magnetic, and those that are, are not really great magnetic storage materials.
Google is less and less helpful for searches like this these days.
Chromium-Manganese (15 % Cr, 12 % Mn, rest Fe) 0,11 mm music, 0.22 mm speech
Nickel (18 % Cr, 8 % Ni, rest Fe) at 0.09 mm
Cheers!
cool. thanks. mind sharing where you found that?
Physical book by
Hans Sutaner: Schallplatte und Tonband. Fachbuchverlag Leipzig, 1954
Good old dead trees.
Sadly, not one on my shelves.
How does it work? No mention in the first few minutes of the video.
Is it magnetised?
Yes, the wire is magnetised by the signal being recorded, so the strength of the magnetic field varies and represents the recorded audio. Very similar to magnetic tape in that respect.
I had one of these that I was given as a kid. I played around with it and still have the microphone to it. The wire is almost certainly not stainless, as I could feel corrosion on some of my reels (and it could reely cut your finger as well). Also, stainless is not the right material for magnetic storage, for which a square B-H curve loop is valuable. The principle is the same as open reel tape recorders, but two things differ. One is that the magnetization is longitudinal (along the wire) rather than transverse as it is in tape. The other is that IIRC the idea of magnetic bias had not been applied yet (and the penetration depth in the wire would make it rather ineffective) and so the high-frequency response and noise of the medium was rather poor.
Mr Carlson is a ROCKSTAR in electronics troubleshooting and repair!
I’m pretty sure aircraft flight data recorders and audio recorders used to just wire for recording, a spool of wire being a lot more likely to survive a crash somewhat intact.
Buzz restored one on his channel recently – worth a look