audio

398 Articles

Surgery On An LED To Preserve Vintage Aesthetics

January 29, 2023 by 53 Comments

[Chris Jones] recently found himself in a pickle. An indicator LED off an old piece of stereo equipment had failed. It was a strange rectangular type for which he could source no modern substitute. Using a different LED would ruin the aesthetic. Thus, what else was [Chris] to do, but attempt surgery on an LED!

The first attempt was the simplest. [Chris] tried soldering a small SMD LED between the legs of the existing part, which was open circuit. It worked, but the light didn’t really propagate to the top of the LED’s plastic. It was too dim to do the job.

Unperturbed, [Chris] instead elected to cut the LED apart. he soldered the SMD LED to the original LED’s leads, inside its body this time. The top part of the plastic lens was then notched to fit snugly over the new SMD part. A bit of superglue then joined everything back together. The finished product looks a touch messy on the PCB. However, installed back inside the stereo, it’s a perfectly stealth fix that looks great.

Some will consider this fix frivolous and a waste of time. Others will appreciate the way it preserved the attractive retro look of a piece of vintage audio gear. In any case, we can all agree that modern LEDs are often a great replacement for older parts in many cases. If you’ve pulled off your own weird, oddball repair hacks, don’t hesitate to share us with them on the tipsline!

plantpot made from recycled audio tape filament in a 3D printer. Pot contains a succulent plant and is surrounded by tape

3D Printer Filament From Reel-to-Reel Audio Tapes

January 12, 2023 by 18 Comments

At heart, 3D printers are just machines that can melt plastic “wire” into interesting shapes. It’s well-known and oft-lamented that plastic of various sorts has been used to make all manner of household objects that might eventually end up in landfill or otherwise littering the environment. With these facts in mind and a surplus of tape, [brtv-z] decided to see if he could recycle some old reel-to-reel audio tapes into working filament for a 3D printer.

The homebrew rig to convert old audio tape into the unconventional filament

This isn’t the first time he has tried to print with unusual second-hand polymers, back in 2020 he pulled of a similar trick using VHS tape. Through experimentation, it was soon determined that seven strands of quarter-inch tape could be twisted together and fused to form a very tough-looking filament approximately 1.7 mm in diameter, which could then be fed into the unsuspecting printer.

The resulting prints are certainly different in a number of respects from using virgin filament. The material is porous, brittle and (unsurprisingly) rather rusty-looking, but it does have some interesting properties.  It retains its magnetism and it catches the light in an unusual way. The video is after the break (in Russian, but YouTube does a reasonable job of generating English captions).

Don’t have any tape handy? No worries, we’ve also covered machines that can recycle plastic waste into filament before. In fact, two of them even won the 2022 Hackaday Prize. What else could you melt down that might otherwise be thrown away?

Continue reading “3D Printer Filament From Reel-to-Reel Audio Tapes” →

AIOC: The Ham Radio All-In-One Cable For Audio And APRS

January 1, 2023 by 23 Comments

The Ham Radio All-in-one cable (AIOC) is a small PCB attachment for a popular series of radio transceivers which adds a USB-attached audio interface and virtual TTY port for programming and the push-to-talk function. The STM32F373 microcontroller (which, sadly is still hard to find in the usual channels) is a perfect fit for this application, with all the needed hardware resources.

With USB-C connectivity, the AIOC enumerates as a sound card as well as a virtual serial device, so interfacing to practically any host computer should be plug-and-play. Connection to the radio uses 12mm separation 3.5mm and 2.5mm TRS connectors, so is compatible with at least the Baofeng UV-5R but likely many other cheap transceivers that have the same physical setup.

Instructions are provided to use the AIOC with Dire Wolf for easy access to APRS applications, which makes a nice out-of-the-box demo to get you going. APRS is not all about tracking things though since other applications can sit atop the APRS/AX.25 network, for example, HROT: the ham radio of things.

We’ve seen quite a few Baofeng (and related products) hacks, like this sketchy pile of wires allowing one to experiment with the guts of the radio for APRS. Of course, such cheap radio transceivers cut so many engineering corners that there are movements to ban their sale, so maybe a new batch of better radios from our friends in the East is on the horizon?

Thanks to [Hspil] for the tip!

Audio Old And New Meet In Perfect Harmony

December 30, 2022 by 20 Comments

There’s an uneasy meeting in the world of audio between digital and analogue. Traditional analogue audio reached a level of very high quality, but as old-style media-based audio sources have fallen out of favor there’s a need to replace them with ones that reflect a new digital audio world. To do this there are several options involving all-in-one Hi-Fi separates at a hefty price, a cheaper range of dongles and boxes for each digital input, or to do what [Keri Szafir] has done and build that all-in-one box for yourself.

The result is a 1U 19″ rack unit that contains an Orange Pi for connectivity and streaming, a hard drive to give it audio NAS capability, plus power switching circuitry to bring all the older equipment under automation. Good quality audio is dealt with by using a Behringer USB audio card, on which in a demonstration of how even some digital audio is now becoming outdated, she ignores the TOSlink connector.

The rear panel has all the connectors for power, USB, network, and audio laid out, while the front has an array of status lights and switches. We particularly like the hand-written lettering, which complements this as a homebrew unit. It certainly makes the Bluetooth dongle dangling at the back of our amplifier seem strangely inadequate.

If audio is your thing, we had a look at some fundamentals of digital audio as part of our Know Audio series.

Wear Your Fave Cassette Tapes As A Necklace With This 3D Printed Adapter

December 29, 2022 by 47 Comments

While packing merch for a recent gig, I realised I had the opportunity to do something a little fun. I’d released an album on tape, and spent a little extra to ensure the cassette itself was a thing of beauty. It deserved to be seen, rather than hidden away in a case on a shelf. I wanted to turn this piece of musical media into a necklace.

Of course, cassette tapes aren’t meant to be used in this way. Simply throwing a chain through the cassette would lead to tape reeling out everywhere. Thus, I fired up some CAD software and engineered a solution to do the job! Here’s how I built an adapter to turn any cassette tape into a cool necklace.

Find the design on Thingiverse, and more details below!

Continue reading “Wear Your Fave Cassette Tapes As A Necklace With This 3D Printed Adapter” →

A radio with a white front grate and wood edges sits on a grey surface. Next to the radio are small white disks with colorful edges reminicient of microdisc-sized records. A yellow-ringed disk sits on the radio. The handwritten title says, "Summer of 2011; Holidays in Barcelona"

Spotify Player Brings Back Physical Media

December 24, 2022 by 21 Comments

Digital music has made keeping all your tunes with you a lot more convenient, but have we lost something with dematerialization? [Jordi Parra] felt that there was something lacking with the digital music experience and designed a Spotify player with a tactile interface.

Specific playlists are selected via small RFID tags that look like a cross between a MiniDisc and a vinyl record. As this is a prototype, an Arduino reads the RFID tag, but needs a computer to actually play the Spotify playlist. Future iterations could include an integrated speaker and run libspotify to create a self-contained device.

While there is still work to do for a fully seamless experience, we love the details in the industrial design of this project. Clean simple lines and a combination of wood and more modern materials make this feel like a timeless piece of tech. Definitely check out the full photo gallery including shots of the really impressive packaging.

Want more digital music with a tactile interface? Check out this MP3 Player Shelf or a Simple Internet Radio Transplant.

How To Restore A Musical Amiga

December 24, 2022 by 21 Comments

Despite the huge strides in computing power and functionality that have been achieved in the past few decades, there are still some things that older computers can do which are basically impossible on modern machines. This doesn’t just include the ability to use older hardware that’s now obsolete, either, although that is certainly a perk. In this two-part restoration of an Amiga 500, [Jeremy] shows us some of these features like the ability to directly modify the audio capabilities of this retro machine.

The restoration starts by fixing some damage and cleaning up the rest of the machine so it could be powered up for the first time in 30 years. Since it was in fairly good shape he then started on the fun part, which was working with this computer’s audio capabilities. It includes a number of amplifiers and filters in hardware that can be switched on or off, so he rebuilt these with new op-amps and added some new controls so that while he is using his MIDI software he can easily change how it sounds. He also restored the floppy disk drives and cleaned up the yellowing on the plastic parts to improve the overall appearance, as well as some other general improvements.

These old Amigas have a lot going for them, but since [Jeremy] is a musician he mostly focused on bringing back some of the musical functionality of his childhood computer, although he did build up a lot of extra features in this machine as well. These types of audio circuits are not something found in modern computers, though, so to get a similar sound without using original hardware you’ll need to build something like this NES audio processing unit programmed in Verilog.

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