Queston: My analog input power amplifier "pops" (artifact in loudspeaker). What is the problem and how do I solve it?
Answer: Good question. This one has been covered in several different papers, but allow me to explain it terms of a differential amplifier. As we know, the output of a differential amplifier is the difference in voltage of its inputs multiplied by its gain. Most of our analog input power amplifiers are differential input; therefore, the input capacitors must match (as close as budget will allow), and the gain of each input must be the same. As the amplifier starts up, the input capacitors are charged through the mid rail bias network inside of the device. If one of the input capacitors is not close to the value of the other input capacitor (+/-10% or better) their difference in charge time will create an error voltage or "pop" on the output of the amplifier. Also, if the gain on the amplifier's inputs does not match, there will again be an error voltage created which will appear on the output of the amplifier.
We recommend +/-10% (or better) X5R dielectric (or better) capacitors and +/-1% resistors for the input networks. Some of the analog input power amplifiers have internal input resistors that are matched during the device manufacturing process.