On Thu, 8 Jul 1999 09:58:31 -0600 Vic Lopez writes: > From here, if I try to raise the gain, the signal gets >distorted. The rest of the experiment conists on having a microphone >pick up >the audible tone from the earphones and feed it to a digital signal >analyzer >to check that the signal is not distorted. If this is a laboratory type setup, where size and power don't matter and cost isn't a big concern, why build an audio amplifier at all? Use an ordinary consumer stereo receiver or PA amp to drive the speaker. If you must build your own amplifier, the LM386 is a good choice for driving to a little more than headphone power. If you need more power, consider one of the 5-pin TO-220 chips like the uPC2002. The 2002 is a little difficult to keep stable. Be sure to use short heavy connections and duplicate the recommended circuit exactly. These are both dinosaur chips, but they are still used in new products so they are likely to stay in production for a while. The CA810 is probably obsolete and not recommended for new designs. ___________________________________________________________________ Get the Internet just the way you want it. Free software, free e-mail, and free Internet access for a month! Try Juno Web: http://dl.www.juno.com/dynoget/tagj.