Only Mechanical Relays Will Do for Automated Hi-Fi Audio Source Switching

If you are a devotee of audiophile-quality analogue hi-fi, switching between sources simply can not be done through a solid-state device. Only physical switches will do because they come without the risk of extra noise or distortion that their silicon equivalents might bring.

That is the philosophy that lies behind [Skrodahl]’s relay-based audio switching board, which boasts 5 high-quality relays each handling a stereo input, with their control passed either to a rotary switch or to an ESP32 module. The ground connections on audio and switching sides are isolated from each other to avoid transient noise finding its way to …read more http://pje.fyi/QKXppf

Paul Jacob Evans

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Chest of Drawers Stores Audio Memories

Some people collect stamps, some collect barbed wire, and some people even collect little bits of silicon and plastic. But the charmingly named [videoschmideo] collects memories, mostly of his travels around the world with his wife. Trinkets and treasures are easy to keep track of, but he found that storing the audio clips he collects a bit more challenging. Until he built this audio memory chest, that is.

Granted, you might not be a collector of something as intangible as audio files, and even if you are, it seems like Google Drive or Dropbox might be the more sensible place …read more http://pje.fyi/PnvVDD

Paul Jacob Evans

The Best Stereo Valve Amp In The World

There are few greater follies in the world of electronics than that of an electronic engineering student who has just discovered the world of hi-fi audio. I was once that electronic engineering student and here follows a tale of one of my follies. One that incidentally taught me a lot about my craft, and I am thankful to say at least did not cost me much money.

It must have been some time in the winter of 1991/92, and being immersed in student radio and sound-and-light I was party to an intense hi-fi arms race among the similarly afflicted. Some …read more http://pje.fyi/PgPQb1

Paul Jacob Evans

How to Do Beautiful Enclosures with Custom Fiberglass

There are times when I feel the need to really make a mess. When I think of making messes with a degree of permanency, I think of fiberglass. I also really like the smell, reminds me of a simpler time in 8th grade shop class. But the whole process, including the mess, is worth it for the amazing shapes you can produce for speaker pods and custom enclosures.

Utilizing fiberglass for something like a custom speaker pod for a car is not difficult, but it does tend to be tedious when it comes to the finishing stages. If you …read more http://pje.fyi/Pc4L87

Paul Jacob Evans

Bessel Filter Design

Once you fall deep enough into the rabbit hole of any project, specific information starts getting harder and harder to find. At some point, trusting experts becomes necessary, even if that information is hard to find, obtuse, or incomplete. [turingbirds] was having this problem with Bessel filters, namely that all of the information about them was scattered around the web and in textbooks. For anyone else who is having trouble with these particular filters, or simply wants to learn more about them, [turingbirds] has put together a guide with all of the information he has about them.

For those who …read more http://pje.fyi/PbSJF0

Paul Jacob Evans

Run From the Sound of Footsteps in Blind Game of Tag

The human auditory system is a complex and wonderful thing. One of its most useful features is the ability to estimate the range and direction of sound sources – think of the way people instinctively turn when hearing a sudden loud noise. A team of students have leveraged this innate ability to produce a game of tag based around nothing but sound.

The game runs on two FPGAs, which handle the processing and communication required. The chaser is given a screen upon which they can see their own location and that of their prey. The target has no vision at …read more http://pje.fyi/PF2Brv

Paul Jacob Evans

Patents on MP3 Format Due to Expire

MP3 took off in the late 90s as the digital music format. It then proceeded to slaughter the CD, and launch the file sharing revolution as well. It’s a proud format that has roots stretching all the way back to the early 1980s, when the possibility of sending music over ISDN lines was first considered. Now the patents on it are beginning to expire and its licencing program has been terminated.

The MP3 standard was the property of Fraunhofer IIS, and the original licencing model was intended such that encoders would be expensive, and decoders relatively inexpensive. This would allow …read more http://pje.fyi/P8kW2f

Paul Jacob Evans