Hi: Colin noted that RF can get into a variety of audio circuits. A case in point occurred last summer on vacation. A small traveler in our party had a Teddy Ruxpin. From time to time the bear would make a ticking sound like a metronome. It took us a while to figure out that this happened when someone in the group was talking on their cell phone. Bob Martin Please visit http://www.wan-leatonks.net.