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Build Your Own Professional-Grade Audio Amp on the Sort of Cheap

Get amazing stereo sound with 3e Audio’s Class-D amplifier board

4 min read
Photo: Randi Klett
Photo: Randi Klett

Years ago I decided to see how little I needed to spend to build a high-end, audiophile quality, class-D amplifier. The answer, then, was US $523.43. I built a worthy little amp, and the article I wrote about it for IEEE Spectrum still attracts page views, and even sporadic emails from people asking where they can get the parts.

Sorry folks, the main components are long gone. So I've been steering people to excellent class-D amplifier kits from Class D Audio, DIY Class D, and Ghent Audio instead. But a couple of months ago I got the itch to see how much better I could do now, almost a decade later, with the same challenge. Part of my motivation was the annual Best Stereo Amps lists from gadget-review website The Master Switch. The lists are dominated by amps costing more than $1,000 (nine of them cost more than $2,000).

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The Transistor at 75

The past, present, and future of the modern world’s most important invention

2 min read
A photo of a birthday cake with 75 written on it.
Lisa Sheehan
LightGreen

Seventy-five years is a long time. It’s so long that most of us don’t remember a time before the transistor, and long enough for many engineers to have devoted entire careers to its use and development. In honor of this most important of technological achievements, this issue’s package of articles explores the transistor’s historical journey and potential future.

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