The VU Meter and How It Got That Way

Given its appearance in one form or another in all but the cheapest audio gear produced in the last 70 years or so, you’d be forgiven for thinking that the ubiquitous VU meter is just one of those electronic add-ons that’s more a result of marketing than engineering. After all, the seemingly arbitrary scale and the vague “volume units” label makes it seem like something a manufacturer would slap on a device just to make it look good. And while that no doubt happens, it turns out that the concept of a VU meter and its execution has some serious …read more

Continue reading The VU Meter and How It Got That Way

Finding The Linear In A Laser

If your path has taken you through any work with hi-fi audio, you will be aware of the effects of distortion on sound quality. The tiniest non-linearity in a component can ruin the result, and people who work at the extreme end of the hi-fi spectrum will go to impossible lengths to chase the tiniest percentages of distortion that no human could possibly hear.

[Monta Elkins] has a Boldport kit, the Lite2Sound, which as its name suggests translates a light level to an audio signal. Given a laser diode and a source of country music from his Amazon Echo then, …read more

Continue reading Finding The Linear In A Laser

A Stereo Tube Amp For Less Than $5

Many of us have aspirations of owning a tube amp. Regardless of the debate on whether or not tube audio is nicer to listen to, or even if you can hear the difference at all, they’re gorgeous to look at. However, the price of buying one to find out if it floats your boat is often too high to justify a purchase.

[The Post Apocalyptic Inventor] has built a stereo tube amplifier in the style of the Fallout video games. The idea came when he realised that the TK 125 tape recorder manufactured by Grundig was still using tube audio …read more

Continue reading A Stereo Tube Amp For Less Than $5

The Hot and Cold of Balanced Audio

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 …read more

Continue reading The Hot and Cold of Balanced Audio

Behind The Pin: How The Raspberry Pi Gets Its Audio

Single board computers have provided us with a revolution in the way we approach computing as hardware creators. We have grown accustomed to a world in which an entire microcomputer has become a component in its own right rather than a complex system, and we interface to them as amorphous entities through their exposed interfaces. But every pin or socket on a single board computer has something behind it, so following up on a recent news-inspired item in which we took a look at what lies behind the Ethernet jack on a Raspberry Pi, we’d like to continue that theme …read more

Continue reading Behind The Pin: How The Raspberry Pi Gets Its Audio

Hybrid Lab Power Supply From Broken Audio Amp

The lab power supply is an essential part of any respectable electronics workbench. However, the cost of buying a unit that has all the features required can be eye-wateringly high for such a seemingly simple device. [The Post Apocalyptic Inventor] has showed us how to build a quality bench power supply from the guts of an old audio amplifier.

We’ve covered our fair share of DIY power supplies here at Hackaday, and despite this one being a year old, it goes the extra mile for a number of reasons. Firstly, many of the expensive and key components are salvaged from …read more

Continue reading Hybrid Lab Power Supply From Broken Audio Amp