IC AMPLIFIERS: There was a time when the use of ICs (Integrated Circuits) in high-end audio was almost universally regarded as undesirable. The first ICs designed in the 1960's and 70's had poor slew rates and a host of other problems, making them inferior to discrete designs. However, times have changed. Over 40 years of collective design experiences have transformed the scene. We now understand more about various mechanisms of distortion and have the advantage of more advanced fabrication technologies and faster transistors. IC power amplifiers built using National Semiconductor's LM3886/LM4780 offer truly exceptional performance, on a par with or even superior to discrete designs. Its sonic potential was first noted by 47 Laboratories, which introduced an IC-based amplifier called Gain Card. It was a paradigmatic shift in the philosophy of high-end amplifier design, and it started a small revolution in the DIY world, with countless hobbyists confirming the quality of its sonic performance. The beauty of the IC amplifier is its simplicity. It is remarkably easy to build, and even novice hobbyists can build a good sounding amplifier out of it. At the same time, it requires just as much attention to details as any other amplifier to obtain the best possible performance. With careful design and tuning, its sonic performance can truly blossom. "Of all our human resources, the most precious is the desire to improve" We started our own investigation by building several versions of IC power amplifiers based on National Semiconductor's Overture series. Through our investigations, we discovered that its potential had not yet been exhausted and that it could be pushed even more to a higher level by optimizing the circuitry around it and the PCB layout. The result of this optimization has demonstrated that the performance of an IC power amplifier can equal or exceed that of expensive discrete designs. The only limitation is its moderate power capability, which still is adequate for most home listening environment.