I had a similar issue happen with my RA 1570. I would hear clicks when I had my Iphone plugged into the front port. It was updated with the right firmware so no idea what it is/was. I sent it back into best buy and it's at Rotel right now. The guy at best buy tested it and said he didn't notice anything....I'm using the 1572 right now while the 1570 gets worked on. I haven't had the same issue so far with 1572.