I'm pretty sure this has been covered somewhere on this or other forums, so I apologize up front. I had an old (7 years old) Pioneer vsx 1021K receiver that would make a single loud pop noise whenever the receiver was powered on. It was loud annoying, but I got over it. Recently I purchased a replacement receiver, a Sony STR-DN1080. So far it has been great except it also makes a single pop when powered on. I'm guessing that it is not the receiver that is the culprit, but I'm not sure in which direction to start my troubleshooting. Does anyone know if there is a common root cause for this type of phenomenon? I thought that the cause was that the old receiver was just that. "Old". But when the new receiver began exhibiting that same issue, I'm thinking maybe the speakers. Is there some kind of filter device that can be installed that could prevent this type of issue? Just trying out different theories. So, if anyone has experienced this and has gotten it to quit, I would be extremely grateful. If not, I guess I can live with the 5 nanosecond pop experience. Thanks!