标签: wire

Before magnetic tape recorders appeared on the scene, their predecessors worked by rapidly pulling a wire over a recording/playback head. To be honest, I'd never even heard about these little beauties until a guy called Nick Gent told me the tale of how his grandfather had built his own wire recorder and made recordings of the family, including Nick's great grandparents and even his mother as a child. Thus it was that, about a year ago as I pen these words, I wrote an article about magnetic wire recorders ( click here to see that original article). Well, it's amazing how these tales keep on growing in the telling, because I was just copied on an email sent to Nick from a guy called Jim Wood who is in the process of constructing his own magnetic wire recorder from the ground up. If there is a right man for the task, that man is Jim. I've since discovered that he and Mark Drake co-founded a company called Inovonics back in 1972. Jim's company is best known for producing high-quality broadcast audio processors, RDS/RBDS encoders, and AM/FM modulation monitors. In his email to Nick, Jim explained that he was Googling "Wire Recorder" when he ran across my article on EE Times and read the story of Nick's grandfather. This made Jim think of an old advert from a 1949 issue of Wireless World magazine (shown below), which advertised parts for experimenters to construct their own wire recorders ("More thrilling than Radio—More gripping than Television"), and which caused Jim to wonder if Nick's grandfather may have been inspired by something like this: Nick responded that Wireless World was indeed quite likely to have been the inspiration for his grandfather, who was avid reader of hobby electronics magazines. Nick also noted that his grandfather probably paid a few visits to Park Radio—the shop advertising the wire recorder parts—because he lived only 20 miles from that establishment. But we digress... It seems that Jim has been a passionate sound recording enthusiast for the better part of 60 years. When Jim was about 13, his dad bought him a used wire recorder, which became one of his most prized possessions. Even after Jim had graduated to tape later in the 1950s, the massive speaker in his wire recorder console cabinet was relegated to subwoofer duties for several years more. Recently, Jim embarked on a project: to build a top-quality wire recorder employing present-day components and techniques. He is using a Webster Chicago mechanism, but is building all of the electronics from scratch. Below we see a shot of Jim's test bed, which he's using to develop the record and playback amplifiers and equalisation circuits: And in the photograph below we see a more detailed view of the breadboarded electronics with annotations explaining the various bits and pieces: Jim says that, thus far, the major hurdle in the design has been accomplishing good low-frequency response. Due to the high wire speed (24 inch (convert to mm except for displays)es (convert to mm except for displays) per second) and the small geometry of the record/reproduce head core, the initial response exhibited severe "head bumps" and egregious deviation from flat low-end response, as illustrated below: Since then, Jim has changed the erase/bias circuitry from a linear amplifier to a power oscillator, which gives a slightly quieter recording. He's also implemented what he describes as "some fancy 'dip' filters" and performed a lot of SPICE simulations to achieve the required equalisation, which is illustrated in the graph of the final overall frequency response shown below: As an example, Jim attached a few seconds of an MP3 recording he made of a transfer from a vinyl LP to his wire recorder ( click here to hear this recording). In his email to Nick and me, Jim modestly noted "It doesn't sound bad at all." I don't think Nick agrees with this assessment, because he immediately responded "The quality of that recording is stunning!" I have to admit that I'm with Nick on this one. Jim says his job is demanding a lot of his time right now (I know that feeling), but when he gets back to this he plans to put it all together in a nice box of some sort and then "do some 'unique' location recording." Jim also says that when the whole thing's finished, he plans on "doing a proper write-up of the project," which I hope he will share with us.  

Do you remember my blog last February when I was waffling on about magnetic wire recorders ? In that column I mentioned that prior to magnetic tape recorders there were magnetic wire recorders . In the case of these little rascals, the recording medium was a spool of wire that was pulled rapidly across the recording or playback head at around 2 fps (feet per second). Ever since I first heard of magnetic wire recorders I've been interested in these little beauties. The way I did hear about them was when a guy from England regaled me with the tale about how his grandfather had built his own wire recorder in the 1940s. When this guy found a box of his grandfather's recordings, he acquired and adapted an old Webster-Chicago wire recorder to play back the spools, whereupon he heard all sorts of interesting things, including the voices of his great grandparents and also his mother as a little girl. Of course these days we are all so used to having digital video cameras and audio recorders that we tend to forget how relatively new these things are in the scheme of things. As recently as the 1930s and 1940s, however, it was rare for non-professionals to have access to any form of recording medium. I don't know about you, but I would love to be able hear my mother's voice from when she was say 10 or 15 years old in 1940 and 1945, respectively (I don't mean that you would want to hear my mother's voice ... stop being so picky ... you know what I mean!) Anyway, the reason I am waffling on about this now is that, a few weeks ago as I pen these words, I received an email from Rick Curl – an engineer who lives in Birmingham, Alabama, which is a couple of hours' drive away from me. A reader of EE Times in general and my columns in particular (he is obviously a man of fine taste and discernment), Rick had only just discovered that I "hang my hat" in Huntsville, Alabama. Since Rick was coming up to Huntsville to pick up some circuit boards that were being manufactured for him, he asked if he might drop round to my office on the way. Well, Rick is a man after my own heart (not the least that he shares my love of Dr. Who). We had a wide-ranging chat about all sorts of things. For example, Rick brought an interesting circuit to show me (and almost electrocute me ... I have a video of the occasion I need to post on YouTube). In turn, I showed him some of the weird and wonderful things I have lurking in my office, including my real-world ENIGMA machine, which had Rick drooling with desire. All of this leads us to the fact that, just a few minutes ago at the time of this writing, a package landed on my desk. In it was a letter from Rick and a small box. In the letter, Rick said that he and his wife Cynthia had been at a flea market near the end of the day when they saw a seller about to throw away a spool of magnetic recording wire because he didn't know what it was. Knowing my love of this sort of thing, Rick kindly sent the spool to me, and I just took a picture of it as shown below:   Here we see the spool itself in the upper-right—a small pamphlet in the lower-right, and the box for the spool in the lower-left. The re-boxed spool now sitting in pride of place on the bookshelves in my office. Now, I'm not sure if this is a virgin reel, or if it contains some recording gem from the past. Eeeek! Do you remember that incredible Dr. Who episode Blink? This episode just popped into my mind. It has me wondering... what if I were to find myself an old Webster wire recorder and load this spool, would I hear an ethereal voice saying something like "Max, listen to this very carefully, because..." ?

Do you remember my blog from earlier this year when I was waffling on about magnetic wire recorders ? In that column I mentioned that prior to magnetic tape recorders there were magnetic wire recorders . In the case of these little rascals, the recording medium was a spool of wire that was pulled rapidly across the recording or playback head at around 2 fps (feet per second). Ever since I first heard of magnetic wire recorders I've been interested in these little beauties. The way I did hear about them was when a guy from England regaled me with the tale about how his grandfather had built his own wire recorder in the 1940s. When this guy found a box of his grandfather's recordings, he acquired and adapted an old Webster-Chicago wire recorder to play back the spools, whereupon he heard all sorts of interesting things, including the voices of his great grandparents and also his mother as a little girl. Of course these days we are all so used to having digital video cameras and audio recorders that we tend to forget how relatively new these things are in the scheme of things. As recently as the 1930s and 1940s, however, it was rare for non-professionals to have access to any form of recording medium. I don't know about you, but I would love to be able hear my mother's voice from when she was say 10 or 15 years old in 1940 and 1945, respectively (I don't mean that you would want to hear my mother's voice ... stop being so picky ... you know what I mean!) Anyway, the reason I am waffling on about this now is that, a few weeks ago as I pen these words, I received an email from Rick Curl – an engineer who lives in Birmingham, Alabama, which is a couple of hours' drive away from me. A reader of EE Times in general and my columns in particular (he is obviously a man of fine taste and discernment), Rick had only just discovered that I "hang my hat" in Huntsville, Alabama. Since Rick was coming up to Huntsville to pick up some circuit boards that were being manufactured for him, he asked if he might drop round to my office on the way. Well, Rick is a man after my own heart (not the least that he shares my love of Dr. Who). We had a wide-ranging chat about all sorts of things. For example, Rick brought an interesting circuit to show me (and almost electrocute me ... I have a video of the occasion I need to post on YouTube). In turn, I showed him some of the weird and wonderful things I have lurking in my office, including my real-world ENIGMA machine, which had Rick drooling with desire. All of this leads us to the fact that, just a few minutes ago at the time of this writing, a package landed on my desk. In it was a letter from Rick and a small box. In the letter, Rick said that he and his wife Cynthia had been at a flea market near the end of the day when they saw a seller about to throw away a spool of magnetic recording wire because he didn't know what it was. Knowing my love of this sort of thing, Rick kindly sent the spool to me, and I just took a picture of it as shown below:   Here we see the spool itself in the upper-right—a small pamphlet in the lower-right, and the box for the spool in the lower-left. The re-boxed spool now sitting in pride of place on the bookshelves in my office. Now, I'm not sure if this is a virgin reel, or if it contains some recording gem from the past. Eeeek! Do you remember that incredible Dr. Who episode Blink? This episode just popped into my mind. It has me wondering... what if I were to find myself an old Webster wire recorder and load this spool, would I hear an ethereal voice saying something like "Max, listen to this very carefully, because..." ?