Bill, It should work fine. Turn bias on and give it a try. 73, Don W3FPR On 8/14/2016 2:19 PM, Bill OMara via Elecraft wrote > Will a Heil headphone (example Pro set) with Icom Element work on a K3 > without any modifications (Just K3 Microphone settings) when plugged into > the rear of the radio? >