mosfet/bipolar transistors

Just a quick point about transistors: when buying a power amplifier do not be snowed by a salesperson who preaches "mosfet" transistors. The Asian manufactureres use mosfet transistors mainly because they are cheap. Intrnational Rectifier makes these under their own trademark: "Hexfets". Unfortunately, mosfets are known for reliability but not for the most accurate audio reproduction. When you go looking, you will notice that the finest home audio amplifiers made all use outputs that are BIPOLAR. These transistors are heavy-duty and high speed but create distortion. Circuit designers who swear by them usually design creative bridge circuits that eliminate all distortion before they reach the speaker wire terminals. Companies like Rockford, Earthquake, and PPI all use mosfets in the driver stages and bipolars for the outputs.