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Sharp Using Digital Amp To Enter Components Market

Sharp will use proprietary high-efficiency amplification technology to enter the high-end audio components market by the end of the year and will later incorporate the technology in audio systems, product marketing manager Pete Bellman said.

The technology, called One-Bit Delta Sigma, will appear late this year in an audiophile-oriented integrated amplifier (amp/preamp) that is said to be the first-ever home audio amplifier that amplifies music in the digital domain.

Its attributes include 5Hz to 100kHz frequency response, more than 110dB dynamic range, super-fast transient response due to a 2.8MHz sampling rate, high resolution, and greater-than-80% efficiency, allowing for cool-running amplifiers in a chassis that can be one-fourth the size of a typical analog amplifier, a Sharp whitepaper said.

The technology, which might be demonstrated at September’s CEDIA Expo, was developed to take advantage of the wide-bandwidth, high-resolution Super Audio CD and DVD-Audio audio formats, but it will also improve playback of standard CDs, Bellman said.

The technology lends itself to inclusion in HDTVs, car audio and PA systems, among other products, but the company hasn’t decided yet whether to do so, nor has it decided whether to license the technology or make it available to other suppliers on an OEM basis.

Sharp’s first one-bit amplifier won’t be small because it is targeted to the audiophile market, nor will it be cheap. The two-channel SM-SX100 integrated amp will feature such costly audiophile trappings as a copper chassis, aluminum cabinet, and gold-plated volume control, and it will be priced at around “several thousand dollars,” Bellman said. It’s rated at 2×100 watts from 5Hz-100kHz into 4 or 8 ohms.

Pricing will be announced closer to the planned fourth-quarter ship date.

The amp will accept direct digital inputs from CD players and SACD players, which are based on one-bit technology similar to Sharp’s, said Bellman.

Sharp, not known in the U.S. in high-end audio circles, is still developing marketing and distribution plans, but distribution could start with custom installers who already sell Sharp LCD projectors.

Possibly as early as 2000, Sharp will introduce additional home audio products incorporating the technology, including a second component amplifier, component-based audio systems, shelf systems, and other compact home audio products. But “there has not been talk of receivers,” he noted. “We’ll probably stick with separate amplifiers and systems.”

Although the technology is roughly equivalent in efficiency to Class D amplifiers, which Sharp calls “quasi-digital” amplifiers because they convert analog voltages into pulses whose duration represents the value of the voltage. But Class D amplifiers have a limited marketplace presence, appearing mainly in subwoofer amplifiers because of such drawbacks as high-frequency noise.

Sharp’s whitepaper said one-bit amplifiers, on the other hand, create a signal that is “a digital representation of the analog input — simply a stream of 1s and 0s that can switch high-power output transistors from saturation to cutoff.” The technology yields lower distortion, wider frequency response, and improved transient response compared to Class D, the whitepaper said.