New Tripath Chip Powers Up Amps

SANTA CLARA, CALIF. — Tripath says it will offer new Class T amplifier chips especially designed for car stereo head units by CES 2002. The new chips will allow onboard amplifiers to produce up to 4 x 70 watts, which marks a significant improvement over current onboard amplifiers that carry a maximum power handing of 4 x 45 watts.

Tripath expects several suppliers to announce the use of the Tripath chips in their head units at CES in January, according to marketing VP Neal Carney.

The new four-channel amplifier chips essentially use digital technology (as do Class D amplifiers) which, while very efficient, tends to cause distortion at higher frequencies.

For this reason all Class D amplifiers are mono amps reserved for use with subwoofers. But Tripath adds feedback and signal processing, which cancels out the distortion so that the amplifiers have the same 90 percent efficiency as digital Class D amplifiers but the fidelity of a linear amplifier, according to Tripath. Thus, Tripath's Class T amplifiers can be used as full range amplifiers.

Because Class T amplifiers give off less heat than linear amplifiers, they also require smaller heat sinks or no heat sink, depending on the power output. While Alpine has used this technology in its amplifiers, Blaupunkt will launch its first amplifier line this month to incorporate Class T technology and has altered the design of the amplifiers to exclude heat sinks. (See story above left.)

The launch of the Blaupunkt amplifiers and the imminent release of the new Class T amplifier chips come at a time when Class D mono amps are beginning to catch on at retailers, and digital amplifiers in general are gaining some marketing buzz.

According to car audio buyer John Leavitt of R.C. Willey Home Furnishings, Salt Lake City, "Class D mono amps seem to be doing fairly well for us. It started last fall. The vendors have done a good job of advertising the advantages of the technology. It could be about 10 percent of our amp sales this year in units."

Similarly, Tobin Waldely, buyer for Magnolia Hi-Fi, Kent, Wash., said, "Generally, the marketing campaign of the 12-volt amp manufacturers is finally catching on and the consumer is educated now. So when they come in looking for an amp, and power is their main concern, they ask for Class D."

Several suppliers, however, claim that Class T technology is not yet perfected, and while Class T amplifiers are very efficient, they do not yet equal the fidelity of linear amplifiers. Said JL Audio VP Manville Smith, "We feel the effort being made is very valuable but the technology is not at the point where it offers the highest fidelity. But in a year or two that could change."

Pioneer "is looking very closely at Class T," according to assistant brand manager Ted Cardenas. Sony marketing manager Phil Lubell said his company is about to ship its first Class D amplifiers and, "At this point, our focus is on the Class D."