If you buy a serious scope these days, it is a good bet it will have at least two channels. There is a lot of value to being able to see two signals in relation to one another at one time. Even though the dual-trace oscilloscope goes back to 1938, they were uncommon and expensive for many years. [Mr. Carlson] found a device from 1939 that would turn a single channel scope into a dual trace scope. In 1939, that was quite the engineering feat.
Today, a dual trace scope is very likely to be digital. But some analog scopes used CRTs with multiple beams to actually draw two traces on the same screen. Most, however, would draw either one trace followed by the other (alternate mode) or rapidly switch between channels (chopper mode). This Sylvania type 104 electronic switch looks like it takes the alternate approach, switching between signals on each sweep using vacuum tubes. You can see the device in action in the video, below.
The inputs and outputs of the device are just simple binding posts, but the unit looked to be in good shape except for the power cord. [Mr. Carlson] does a teardown and he even traced out a hand-drawn schematic. Fair warning. The video is pretty long. If you want to get right to the switch actually driving a scope, that’s at about one hour and seven minutes in.
We doubt we’ll see a tube-based Quake game anytime soon. If you want to get into restoring old tube-based gear yourself, you could do worse than read about radio restoration.
Continue reading “Dual Trace Scope 1939 Style”
For most of us who have experimented with Morse code, the oldest key we are likely to have used will have been a piece of military surplus kit from the Second World War era. [Kyle Gabriel] however is a lucky man. His grandfather left him his key-on-board telegraph practice set, a vintage key and telegraph sounder arrangement used to learn Morse code in the days when the telegraph was king. Rather than keep the set merely as an heirloom, [Kyle] set about bringing it up to date by interfacing it to a Raspberry Pi and writing a Morse reader program.
Along the way [Kyle] had to contend with debouncing the switching signal from the key, considering an RC network before settling on a software debounce timer. He provides a brief synopsis of the mechanics of Morse decoding software, and a demonstration of the code in action which you can see in the video below the break.
[Kyle’s] decoding software, beatbybeat, is on GitHub. We can see it will be a useful tool for anyone interested in Morse, or who is writing their own Morse software.
Morse code has featured on these pages more than a few times over the years. Of relevance to this piece are an Arduino decoding Morse code, a more up-to-date practice oscillator with a home-made key, and a couple of other vintage telegraphs reading RSS feeds and reading emails.
Continue reading “Breathing New Life Into An Old Key”
We always like seeing projects that salvage a classic piece of technology, and this one doesn’t disappoint. It’s a vintage kiosk- or console-style stereo, repurposed with every useful feature imaginable, but still made to look original. Until you open the lid, that is.
[Julian] has been hard at work on rebuilding this 1957 RCA stereo, and since he’s no stranger to these types of rebuilds, the results are pretty impressive. Underneath the hood is a 22″ touchscreen running Windows 7 and a Lepai amplifier. The controls for the stereo were placed towards the back, along with USB ports and an RJ45 connector for the computer.
The speakers in the stereo also needed to be replaced. For this, [Julian] used a set of Dayton speakers that worked well enough for this application. After mounting the speakers and all the other hardware in the unit, [Julian] noted that while it isn’t an audiophile’s dream stereo, it was nice to have all of these parts integrated together into something that looks nice. We’d have to agree!
There are a lot of rejuvenated antique stereos around too, like this Bluetooth-enabled tube amp radio, or this Soviet-era handheld, or even this slightly more modern stereo. There’s just something classy about having a vintage-looking thing spruced up with modern technology!
Every family has an heirloom. It might be a watch, a book, or a stuffed pet. [Mike’s] family heirloom was an antique violin. Well, not an entire violin. This particular violin consisted of a detached neck, a body, and one tuning peg. As far as [Mike] knows, no living member of his family has heard it played. [Mike] decided to restore it to playable condition.
[Mike’s] violin had been brought over to America when his family emigrated from France. The primary reason it has been saved is because it bears the name Stradivarius. Stradivarius copies and tributes are plentiful in the wild. Many of the copies are now antiques and good playing instruments in their own right, though not nearly as revered as the real thing. [Mike’s] first step was to determine if his violin was a real Strad, or a copy. Luckily he was able to get in touch with the caretaker of a real Strad in Milwaukee. It turns out that the label on his violin marks it as a copy. According to the caretaker, genuine Stradivarius instruments were signed directly on the wood. The caretaker was further able to identify that [Mike’s] violin was about 100 years old, and a relatively cheap model for the time.
While it wasn’t a real Stradivarius, the violin was still an important part of [Mike’s] family history, and deserved to be played again. Rather than re-create the missing parts to perfectly match the originals, [Mike] decided to use the resources of the Milwaukee Makerspace to create 3D printed parts.
Similar violin parts were scanned at the Makerspace. The final .stl files were sent to Shapeways for printing. [Mike] sent all the parts to a luthier for final fitting and assembly. [Mike’s] family heirloom is no longer an item to be hidden away, but a living breathing instrument for a new generation to enjoy.
The before image doesn’t look all that bad but we were still impressed with what went into the restoration of this radio. Perhaps restoration isn’t the right word since it didn’t manage to hold on to any of the original internals. This is more resurrection of a retro radio case for use as a Bluetooth radio.
At first look we didn’t notice that the original knobs were missing. The speaker fabric is ripped and the glass on the tuning dial is broken as well. [Yaaaam] happened to have another antique radio with interesting knobs — but he didn’t just transplant them. He made a mold of one knob and cast three replacements for the radio. After refinishing the wood he replaced the fabric and things were really starting to look up.
All of the electronic components were removed and a new tube amp was built on the original metal chassis. It uses a Bluetooth module for input which facilitates using your smart phone as the playback device without involving any wires or other nonsense. Two problems popped up after the project was completed. The first replacement power supply overheated. The second replacement had a different problem, needing some additional shielding to prevent noise from creating unwanted… noise.
This looks so much better than modern injection molded plastic shelf systems. But there are some fun wireless hacks out there for those too.
[Simon] is in the middle of restoring/building himself an Austin 7 Special out in his garage, and like most tinkerers, found that music helps to move the process along. He happened to have an old Bakelite generator phone out in the garage as well, and figured that he might as well have it do something other than simply hang on the wall.
Playing music from the 1930 seemed like a fitting enough task, so he picked up an Adafruit Waveshield and spent some time wiring it up to the old telephone. His new radio works simply enough, piping .wav files through the handset, provided someone has cranked the phone’s generator recently.
While cranking the generator is required to play music, the Arduino is actually powered off a pair of AA batteries. The cranking is all cosmetic, but he did program the Arduino to slow the music down every once in awhile, requiring that the generator be turned to get things back up to speed.
It really is a neat way to repurpose the old phone, and we like the fact that [Simon] did not gut it to put this project together.
Continue reading to see a short video of his new music player in action.
Continue reading “Antique phone provides a soundtrack perfect for restoring old cars”
Reader [Jimmy] sent us some info about his recently completed antique radio to audio streamer conversion. The electronics from the original radio were too far gone to repair, but he took the time to pull apart modern components to provide a polished looking finished project without losing the antique feel. We like it, but we are just suckers for that old time look. Check out his blog for more photos.