If you're outside of N. America... chances are pretty good you're going to require the 240v version as that's what the line voltage is in most of the world [except N. America and Japan].
If you're in N. America... you need the 120v version as that's the line voltage that comes out of the electrical sockets.
does the larger powersupply have a positive effect on the sound? cuz i know thats a big problem with cheaper gear inconsistent power from the PSU, which hurts the sound of the gear....
Kind of like the old '18 volt bat in the RadioShack PZM' trick?
It could work if it needed it in the first place, which it probably doesn't, and if the extra actually got to the unit. If both trans spit out the same volts/amps it wouldn't.
Wayne