I have an A55,with musics on my SD card. I tried deleting some tracks using the folder explorer on the Walkman but it said cannot delete. Any ideas about this? I still can delete if I plug my walkman to my PC using Windows Explorer

I have just purchased an RS1e today and compared it with my old 125e. I haven't felt the difference in price between these 2 models. The Rs1e has a more detailed sound, better soundstage, smoother mid and treb and better seperation, but I just didn't feel that it's worth the upgrade. The...