Hi, all! Many thanks for advice so far! Dopey question time again! Now I've got hold of a Shure SM58 mike and connected it direct to my R55 Minidisc mike socket via a stereo 1/8th inch plug. The mike sounds, not too sensitive, which is fine for the speech recording I want to do outdoors. BUT in the background is a very obvious twittering sound, as if I'm recording in a copter! It sounds like motor noise, yet the mike is on a 5-foot cord, and the Minidisc sounds smooth enough running. Have tried a new disc in it, but no change. But when I use a headphone as a mike, there's no trace of the background noise. Any ideas, please? Could it be impedance problems? The Minidisc unit was purchased used from eBay but was reported to be hardly used and seems in perfect condition otherwise. It came with a disc of music the owner had recorded, and there's no trace of the background noise on that. Many thanks! Johnny, Mqanchester, England.