New from Audio Designline is this three page FAQ on class D audio amplifiers. Not extremely technical, but it answers many questions for the technically minded. I remember studying class D amplifiers many years ago in college. In those days the quality was decidedly not hi-fi and the reliability was somewhere in the vicinity of a well-worn Yugo. How times change. Now they seem more common than fly dung and class D controller ICs and ASICs are offered by numerous manufacturers.