It’s often said that the music etched into a vinyl record takes on a transcendent quality that you simply can’t find in a digital recording, but does that still apply when you add motion picture? The collaboration of [Sengmüller and Diamant] sure think so, because they are offering a new experience for the turntable with the introduction of their VinylVideo pre-amplifier. No tape reels here, this project shows the extend of what is possible through analog video.
While all record players capable of playing back 7 in. 45 RPM are compatible with the system, the VinylVideo records themselves specially cut in order to generate the video signal. Each of the custom records has room for a 4-minute music video on the A-side, and the single on the B-side. Videos play back in black & white, sub-standard definition with mono audio, and run around 12 frames per second. The pre-amp takes in the analog signal from regular audio cables via RCA jacks or 3.5mm headphone jack, and then a Raspberry Pi model A+ handles the analog-to-digital conversion. Video out options include HDMI and composite video via a 3.5mm TRSS jack.
The current VinylVideo pre-amp is actually a refinement of the original project from the mid ’90s where it was a part of folk art exhibits. The legacy website (circa 1999) is still live, so you can give it a visit. However, for the most authentic experience you may want to fire-up a virtual machine with Netscape Navigator and Real Player installed.
For a more in-depth look at the VinylVideo in action there is a great video below from [Techmoan]:
With all due respect to the hackers and makers out there that provide us with all these awesome projects to salivate over, a good deal of them tend to prioritize functionality over aesthetics. Which isn’t a bad thing necessarily, and arguably better than the alternative. But for many people there’s a certain connotation around DIY, an impression that the final product is often a little rough around the edges. It’s usually cheaper, maybe even objectively better, but rarely more attractive.
Which makes builds like this absolutely beautiful 3D printed Bluetooth speaker by [Ahmsville] especially impressive. Not only did he engineer a fantastic sounding speaker that projects stereo sound no matter where you are in the room, he clearly gave a lot of thought into making the final product look as good as it sounds.
The 3D-printed enclosure provides separation for the four internal speakers and two passive radiators, as well as holding the electronics. A custom made 3S battery powers the Bluetooth module though an isolated step-down module, and the twin 18 W TDA2030 amplifiers feed their respective pair of drivers.
The device is surrounded by an impressively detailed 3D-printed mesh, which is then wrapped with some speaker grill fabric to give it a very professional look. In the video after the break, [Ahmsville] shows a time-lapse of building the speaker, as well as a demonstration of how it sounds on his desk.
At first glance, this fire engine red speaker box built by [NoshBar] looks straightforward enough. Just an MDF case and couple of drivers recovered from a trashed stereo. But the array of controls and connectors on the front, and a peek on the inside, shows there’s more to this particular project than meets the eye.
Built almost entirely from parts [NoshBar] found in the trash, construction started with some salvaged MDF IKEA shelves and their corresponding twist lock cam fittings. We don’t usually see those style cam fittings used to build DIY enclosures, but if it works for all those furniture manufacturers why not?
A pair of Sony stereo speakers he found gave up their internals, and a TPA3116 amplifier board off of eBay drives them. He’s wired up an audio pass-through mode for using headphones when the amplifier is powered off, and dual inputs so he can switch between PC and PS4.
But the audio components are only half of what’s inside that shiny red exterior. [NoshBar] packed in an ATX PSU and broke out the 3.3 V, 5 V, and 12 V lines to the front panel so he can use it as a bench power supply for his Arduino projects. It’s also home to a gigabit Ethernet switch and a Raspberry Pi acting as a file server.
Sometimes I wish FETs had become practical before bipolar transistors. A FET is a lot more like a tube and amplifies voltages. Bipolar transistors amplify current and that makes them a bit harder to use. Recently, [Jenny List] did a series on transistor amplifiers including the topic of this Circuit VR, the common emitter amplifier. [Jenny] talked about biasing. I’ll start with biasing too, but in the next installment, I want to talk about how to use capacitors in this design and how to blend two amplifiers together and why you’d want to do that.
But before you can dive into capacitors and cascades, we need a good feel for how to get the transistor biased to start with. As always, there’s good news and bad news. The bad news it that transistors vary quite a bit from device to device. The good news is that we’ll use some design tricks to keep that from being a problem and that will also give us a pretty wide tolerance on component values. The resulting amplifier won’t necessarily be precise, but it will be fine for most uses. As usual, you can find all the design files on GitHub, and we’ll be using the LT Spice simulator.
This Bluetooth speaker is full of delightful surprises. The outer shell is an antique radio cabinet, but its practically empty interior is a combination of Dead Bug circuitry and modern BT receiver.
[PJ Allen] found the BT receiver on Groupon and decided to whip up amplifier and threshold detector circuits using only parts he already had in order to make this vintage-looking Bluetooth speaker. The cabinet is from a Silvertone Model 1955 circa 1936. Don’t worry, no antiques were harmed in the making of this hack, the cabinet was empty when he bought it.
The amplifiers, one per speaker, began life as a circuit from TI’s LM4871 datasheet. Some of the departures came about because he didn’t have the exact component values, even paralleling capacitors to get in the right range. The finished board is a delightful mix of “Dead Bug” and quasi-Manhattan style construction, “quasi” because he carved up the ground plane instead of laying pads on top of it.
Look at the front of the cabinet and you’ll see a rectangular display. Watch the video below and you’ll see that it throbs in time to the music. To do that he came up with a threshold detector circuit which started out based on a circuit from a Sharp/Optonica cassette tape deck, but to which he made improvements.
A few summers of my misspent youth found me working at an outdoor concert venue on the local crew. The local crew helps the show’s technicians — don’t call them roadies; they hate that — put up the show. You unpack the trucks, put up the lights, fly the sound system, help run the show, and put it all back in the trucks at the end. It was grueling work, but a lot of fun, and I got to meet people with names like “Mister Dog Vomit.”
One of the things I most remember about the load-in process was running the snakes. The snakes are fat bundles of cables, one for audio and one for lighting, that run from the stage to the consoles out in the house. The bigger the snakes, the bigger the show. It always impressed me that the audio snake, something like 50 yards long, was able to carry all those low-level signals without picking up interference from the AC thrumming through the lighting snake running right alongside it, while my stereo at home would pick up hum from the three-foot long RCA cable between the turntable and the preamp.
I asked one of the audio techs about that during one show, and he held up the end of the snake where all the cables break out into separate connectors. The chunky silver plugs clinked together as he gave his two-word answer before going back to patching in the console: “Balanced audio.”
Reading an article about the first transistorized Hi-Fi amplifier, [Netzener] got the itch to make one. But what to use for the starting point? Enter an old Radio Shack P-Box stereo amplifier kit. After a few modernizations and tweaks, the result is an 8-transistor stereo amplifier that’s aesthetically pleasing, sounds great, and is fully documented.
The Radio Shack kit used germanium transistors, but with their high leakage current and low thermal conductivity, he decided to convert it to work with silicon transistors. He also made some improvements to the push-pull bias circuit and limited the high-frequency response. As for the finished product, in true [Netzener] style, he assembled it all to look like the original completed Radio Shack amplifier. He even wrote up a manual which you’d think, as we did at first, was the original one, giving that old, comfortable feeling of reading quality Radio Shack documentation.
Check out the video below where he uses a 9 V battery and half a watt per channel to fill a room with clear, stereo sound.