Apogee Technology has complained about some of Texas Instruments Inc.'s Class D claims. In March, TI called itself the first to introduce a single-chip Class D amplifier in the 125-watt/channel range.

One of my first jobs as an engineer was at Empire Scientific Corp. in Garden City, NY in 1972. This was a high-end audio company that made speakers, turntables and phonograph cartridges. We had some ...