Theta's class-D Powerhouse

Photograph: Larry Greenhill

Theta Digital, the pioneer of digital separates, announces the mighty Prometheus monoblocks ($12,000/pair). Heard in pre-production mode, with bass so strong and tight that it sent me into the hallway to discuss the product, the 200Wpc into 8 ohms monoblock is due out "within 90 days" (to quote a mantra oft-repeated at CES 2013).

According to the company's designer, Dave Reich, the Prometheus is based on a European-sourced module, which is mated to Theta's own power supply, software, and hardware control. "Timing between switching on and off is crucial in class-D amplifiers," he said. "I've been listening to switching-amp modules for 10 years, and ours is one of only two I've liked." Replacing Theta's Enterprise monoblock, the amp includes both single-ended and true balanced inputs.—Jason Victor Serinus

Larry Greenhill comments: ATI Audio's Senior Vice President, Jeff Hipps, explained that the Hypex NC-200 modules used in the Prometheus solve a major design problem with class-D amplifiers. Unlike a class-AB amplifier, Hipps explained, the class-D amplifier's output stage must employ a low-pass filter to block the noise generated by the 400kHz switching frequency. With conventional class-D amplifiers, this filter interacts with the speaker load, but not with the Hypex technology. Hipps and his associates at ATI amplifier Technologies believes that the Prometheus 6000 monoblock is one of the most neutral, least-colored class-D audio amplifiers on the market today.