I use isolation or center-tapped (balanced), step-down transformers on almost all my gear, all rated for 115V, including sources and 2 class A monoblocks. The exception being a dedicated, class AB, bass amp. The current swings for the latter 4X400W amp would be tough, but not impossible, to keep up with but since everything else was isolated, it wasn't necessary. Even had a regulated (ferroresonant) iso tranny for the plasma TV for a while but it was too noisy.
The only sonic difference, as compared to wall outlet, should be less noise. If there is a change in the "character" of the sound, something might be wrong either way.
The only sonic difference, as compared to wall outlet, should be less noise. If there is a change in the "character" of the sound, something might be wrong either way.