Cool Runner
Sydney Morning Herald
Monday February 12, 2001
SHARP is not a name normally associated with esoteric two-channel amplifiers, so it was a surprise last year when the company released its $25,000 SM-SX100 amplifier. The company justified the price tag by saying the SM-SX100 was the first of a new breed of digital amplifiers that consumed little power and produced almost no heat.
This year, Sharp has made good on a promise to reduce the cost of digital amplifier technology by releasing the SM-SX1. It's certainly less than half the price of its bigger brother, but it's also half the size and produces less than half the power, with a continuous rating of only 50 watts RMS per channel into 8 ohms.
Rather than follow the space-age styling of the SM-SX100, Sharp has copied a style it developed for its DX-SX1 Super-Audio CD (SACD) player, so the SM-SX1 has a mirror-faced, wedge-shaped front panel from which protrude two controls, one for power switching and one for volume. Input source selection is handled by five small push-buttons.
One of these activates a special SACD input that takes the Super-Audio digital data from the DX-SX1 player and runs it directly to the output stages of the amplifier, ensuring the audio signal remains in the digital domain for as long as possible. Unfortunately, this requires the use of a special 13-pin cable and a standard digital cable for use when playing back compact discs. Worse, there is no automatic format switching, so you must manually change inputs when you change discs, a task made more difficult because the SM-SX1 lacks a remote control.
The Super-Audio CD format was developed by Sony and Philips as a high-fidelity, multi-channel version of the CD. Despite SACD's outstandingly good sound, Sony and Philips are having difficulty interesting other manufacturers. Two years down the track only Sony, Sharp and Marantz (a Philips subsidiary) have released SACD players. More significantly, only a hundred or so SACD titles have been pressed. Manufacturers seem content to wait to see how a competing high-fidelity format, DVD-Audio, will fare.
Digital amplifiers share many advantages, but also share two significant failings. The first is high output impedance, so they cannot control unwanted movements in a loudspeaker cone as effectively as conventional amplifiers, whose output stages have much lower impedance. The second is that the output impedance of a digital amplifier increases to more than 2 ohms at high frequencies. This means the treble performance of a digital amp is affected by the impedance of speakers. It is best to use speakers that incorporate impedance compensation.
Sharp has certainly slashed the cost of digital amplifier technology, but for the most part the SM-SX1 will be no more affordable than the SM-SX100. There is hope, however. At last month's Las Vegas Consumer Electronics Show, Sharp previewed a range of mini-systems that incorporated the technology. These should become available in Australia sometime later this year. Stay tuned.
Greg Borrowman is the editor of Australian HI-FI Magazine.
info file
Sharp SM-SX1 1-Bit Digital Amplifier
Price: $10,000
Sharp Corporation, 1 Huntingwood Drive, Huntingwood, NSW 2148
9830 4600
customercare@sharp.net.au
www.sharp.net.au
© 2001 Sydney Morning Herald