The only requirement for wall chargers to be compatible with all Sony devices - x50 and Tx is that chargers have to be complaint with EU cell phone charging standard. As part of the standard 2 middle wires (out of USB four) should be short circuited, so device will recognize that this is charger and not a computer. Most of the phones today have complaint chargers - most, but not all. As it was mentioned here Apple uses those wires differently - it puts some voltage between wires, so device will know how much current to draw and chargers from iPad are different form chargers for iPod in this sense - or at least they used to be. Blackberry chargers often do not bother with standard at all - since Blackberry devices (at least the ones I have) could charge from anything. So for myself I bought
usb extension cable, cut it to short length, shorted 2 middle wires on the device end, left 2 middle wires on the charger end isolated and put everything back together. Now when inserted between reader and charger this thing allow me to charge from any charger - complaint or not. It works with all chargers I tried for all my x50, T1 and T2.