Counterpoint Natural Progression NPS-400 power amplifier

Counterpoint Natural Progression NPS-400 power amplifier

Amplifier designers have frequently looked for ways to marry the advantages of tubes to those of solid-state devices. Hybrid designs of various stripes have appeared over the years, most of them using tube input stages with transistor output stages, eliminating the major weaknesses of tube amplifiers: eg, they run hot, are unreliable in that tubes have a finite life, are more expensive than a similarly powerful solid-state design, and have power-hungry output tubes and output transformers.

Acoustic Energy AE2 loudspeaker

Acoustic Energy AE2 loudspeaker

In the September 1988 issue of Stereophile, I wrote a rave review about the first speaker, the AE1, from what was to me a totally unknown English company, Acoustic Energy. Though tiny, and possessing an intrinsically limited low-frequency response, the $1500/pair AE1 was one of the most musical loudspeakers I have ever used, throwing a deep, beautifully defined soundstage, and possessed of a clean treble and a sweet, if rather forward-balanced, midband.

Analog Corner #288: I've Been Everywhere

Analog Corner #288: I've Been Everywhere

I went everywhere!

Attending the two-day Making Vinyl Berlin B2B conference on May 2 and 3, 2019 was an obvious decision for me, even if Day 1's "Physical Media World Conference" panel discussion was more about optical digital media than it was about analog vinyl.

The FTC Proposes Eliminating Its "Amplifier Rule"

The FTC Proposes Eliminating Its "Amplifier Rule"

When I joined Hi-Fi News in the mid-1970s, one of that magazine's stable mates reviewed cars. An automotive writer appeared in the pub one lunchtime—"I rolled another one," he said, as he joined us at the bar. It turned out that one of his tasks was to take a car he was testing to the skid pad to see how many lateral G's the car could handle. Of course, the chances of a consumer turning that car over were minimal, but the reviewer was investigating the edges of the performance envelope.

As I became familiar with audio measurements, it struck me that the equivalent of the skid pan test was the thermal preconditioning we perform when we get an amplifier on the test bench. Even if an end-user doesn't drive his amplifier into thermal meltdown, the edges of the envelope need to be explored.

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