NBS Universal Power Amplifier

NBS is perhaps best known for high-end cables—its URL is nbscables.com, after all—but this American boutique audio company also makes a few unusual speakers and electronic components. I'm especially intrigued by the Universal Power Amplifier (UPA), a unique monoblock that is truly universal in design and operation.

The first thing you notice is the UPA's three separate sections—the short one in the middle is the power conditioner, and the two tall ones house the power supply and audio circuitry, keeping them completely isolated from each other. The amp will operate perfectly well with any AC voltage from 85 to 265V, which encompasses everything from brownout conditions in Japan to high-line voltage in Australia.

Another universal aspect of the UPA is its load tolerance—it can safely deliver a minimum of 600W to speakers with a nominal impedance of 2-16Ω, and even a short circuit doesn't bother it. Also, the amp offers switchable balanced and unbalanced inputs as well as a stepped input-attenuation control to optimize its gain for whatever preamp you might use with it.

This Class D amp is analog all the way—"D" doesn't stand for "digital"—and designed so that its frequency response is unaffected by changes in the speaker's impedance at different frequencies. In fact, the company has implemented a number of sophisticated technical ideas to ensure the best possible performance. So how does it sound? I have no idea, but for $80,000 each, it had better make angels weep!