Lets say you are generating some tones into a mono headphone, what could be = used to give say 32 levels of volume and also function as the headphone driver? = Any ideas? I am thinking along the lines of 5 IO lines on a PIC processor adjusting in and = out resistors on some type of opamp? Ideas? Richard. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.