Article on the SI Amp

Just came to know theat the designer of the Tripath chip is of Indian Origin

http://www.forbes.com/business/global/2005/1003/026A.html

Cheap Beats (article by Daniel Lyons forbes.com)

A $39 amplifier blows away audio gear costing thousandsof dollars. Its makers were the last to know.
As gadgets go, the T-Amp was nothing to brag about, just a $39 battery-powered amplifier that hooks up to chintzy cardboard speakers. A firm called Sonic Impact Technologies introduced it to no acclaim in 2003. Then orders suddenly took off last fall, surging from a hundred to a thousand units a week. Richard Bracke couldn't figure out why. He and his partners at Sonic Impact had created the T-Amp as a toy, an AA-battery-powered plaything for kids at the beach.

He called a customer and learned that audiophiles were raving about the T-Amp on the Internet, claiming this tiny plastic wedge produced music as sweet-sounding as amplifiers costing thousands of dollars. The customer had "hooked it up to an $18,000 pair of speakers and a $6,000 CD player," Bracke says. A reviewer on a Web site in Italy called the T-Amp the most amazing product in 25 years. And an online cottage industry had sprung up around the T-Amp, with companies such as Red Wine Audio, in Auburn, Massachusetts, stuffing the electronic guts of the plastic amps into sleek metal cases and selling them for up to $1,200.

Bracke was stunned. Nobody at Sonic Impact had considered the T-Amp to be anything special. Its sound turns ragged at high volumes, and it comes with low-quality plugs and speaker connectors. But the online hype has emboldened Sonic Impact to come out with a line of pricier home audio gear based on the T-Amp.

Sales at the privately held firm almost quadrupled to $5.5 million last year, driven by a squarish pair of flat-panel speakers that hook up to a laptop or an MP3 player. This year Sonic Impact hopes to exceed $25 million in sales, with the debut of the i-Fusion, a new speaker-cum-carrying-case for Apple's iPod. The T-Amp will deliver a mere $250,000 this year but has generated far more value in stirring scads of good PR.

"The T-Amp has created this little whirlwind for us, a sort of underground buzz,"Bracke says.

A fortuitous meeting, a breakthrough microchip and a love of outsourcing had a lot to do with it. Bracke was working as a bodyguard and chef in 2000 when he met Robert Cotton and Mark Zickel, partners in another business called Omni Swings-n-Things, which makes $60 hammocks sold on Amazon.com.

None of them had engineering backgrounds, but they recognized that portable audio was going to boom yet again and wanted to go after it. Zickel and Cotton put up $500,000, and by 2001 their first product, a set of speakers using flat-panel technology developed by NXT, a British company, had become a huge hit with laptop computer owners. Over the next two years SonicImpact introduced new versions of the speakers (the SI-5) and an FM transmitter that beams music from a portable player to a stereo.

In 2003 engineers at chipmaker Tripath Technology of San Jose, California showed Cotton a tiny amplifier with an innovative chip used to power speakers in plasma TV sets made by Samsung,Sanyo and Sharp.

Typical amplifiers boost audio signals by varying the voltage (higher voltage equals louder sound). Tripath's chipamplifies signals by pulsing power on and off like a light switch (longer pulses result in louder sound). These so-called Class D amplifiers are more efficient than traditional models because they are always either at maximum voltage or off, nothing in between, so they waste less energy and produce less heat. The downside is that typical Class D amps produce more distortion, so usually they are relegated to subwoofers, which produce thumping bass that sounds fine despite modest distortion.

But Tripath's founder, Adya Tripathi, figured out a way to make a digital amplifier that produces very little distortion.Tripathi, a Ph.D. in electrical engineering and a veteran of National Semiconductor, Advanced Micro Devices and IBM, found that part of the trick involvespulsing on and off at far higher rates--millions of times per second instead of 100,000 per second for Class D designs.Tripath's higher pulse rate creates more chances to offset signal distortion by applying feedback. Tripath calls its design ClassT amplification.

For the folks at Sonic Impact the beauty of the Tripath amplifier was that it could be powered by AA batteries and most of the engineering had already been done by Tripath, which provided designs for the circuit board that goes with it. Sonic Impact outsourced design of the case and a few engineering tweaks and manufacturing to partners in China.

The T-Amp uses Tripath's lowest-end chip, the model 2024, which puts out 15 watts of power and costs $3; its most powerful chip puts out 500 watts, costs $45 and is found in high-end stereo gear costing thousands of dollars. Other than power, there isn't much difference; the chips all use the same basic technology.

The $39 plastic T-Amp hit the market in September 2003. Within six months audiophiles began buzzing about it on the Web, and orders started rising. Sonic Impact now cranks out 4,000 T-Amps a month. New models are coming out, including one with the same chip as the plastic T-Amp but boasting a metal case and heavy-duty speaker connectors for $139, followed next year by a 50-watt version that will cost $349.

The self-funded company has been profitable since 2003, in part because it has only fiveemployees. Bracke and his partners know the T-Amp craze won't last. Anyone can lay their hands on Tripath's chips and rush out a knock-off. So they are playing it safe, still building only 2,000 T-Amps every two weeks. "Just in case,"Bracke says.