Curious, have you tried moving the amp to a different spot to see if that improves the wifi signal? I remember some years ago at a different house I had a Squeezebox radio in the kitchen that was having connection problems like you dscribe. It turned out the washing machine and dryer were directly in the path between the radio and router. Moving the router about 2 or 3 feet solved the problem. Since the washer/dryer were in a closet out of sight the "line of sight" pathway wasn't immediately obvious.
