I've had my 545's for over 3 years, and am noticing now that the cable connection seems to be getting flaky. It seems like I havta push the cable-plugs into the headphones at just the right pressure in order for them to work... otherwise, the sound cuts out. Is this a common problem when the cables get old? Would ordering a replacement cable from Sennheiser's website fix this problem? If so, is ordering direct from Sennheiser the best way to go, or are there better online places to order from? Thanks for any help!