There is a ACC1 line out of the PX3 that the amp cable plugs into. See page 9 of the PX3 manual. -- View this message in context: http://elecraft.365791.n2.nabble.com/KXPA100-KX3-PX3-Question-tp7624810p7624812.html Sent from the Elecraft mailing list archive at Nabble.com.