Step Up/Down Transformers - Good or Bad?


I have an amplifier that was purchased in Europe and I am using it here in the States. I am having to use a step up transformer in order to connect between the wall and the amplifier. Is there a compromise to the sound with any transformer that is placed between component and wall outlet? Does it all depend on the quality of the transformer? Can one use an after-market power cord and have it yield benefits, even if it is plugged into the transformer?

Appreciate the responses.
glrtrgi
Detlof have answered the same way I would have. I don't like transformers hanging on amps.

In my system I use one isolation transformer that drops (USA) 120 Volt to (Japan) 100 volt to supply the motor controller for my Technics MK3. Even though it's a simple job, I opted for a large transformer rated 10 times over, in hope it would not damage performance.

As Detlof said, transformers typically damage dynamics and I've had my share here for trial.
Me - "twice the volts gets you twice the amps". In context of electrocution hazard.
Ngjockey - "BTW,twice the volts is half the amps". In context of transformer characteristics.

Alberporter & Detlof - Thanks for the feedback. 'Damage dynamics' gives me a bit more to think about.

Regards
Hmm.
1. We all like specific types of disortion in our audio. My personal favorite is the high magnitude even order harmonic distortion that you get with vaccum tubes.
2. It seems reasonably well established that distortion in the upper frequency range can make music sound more dynamic. For example Vandersteen goes to the expense of installing back firing tweeters on their 5a's because some listeners/systems benefit from the timing and frequency distortion inherent to bouncing tweeters off of back walls & etc.
3. If a person is basically happy with their system & then they insert a device that tends to eliminate higher frequency distortion would this most likely be percieved as a loss of dynamics?
"My personal favorite is the high magnitude even order harmonic distortion that you get with vaccum (sic)tubes."

Not to get off topic but the more accurate statement is, if tubes have distortion it is more likely to be even order.
The better tube designs can sound quite neutral.
Gregadd - "tube designs can sound quite neutral." Agreed, but would they still sound neutral without signal distortion? I think that the electrical distortion which creates the illusion of natural acoustic distortion, or tends to fill in the signal loss inherent to recording & playback, is part of what we like about our systems.