One more piece of advice. I was using a 110V guitar amplifier from North America after I moved to China. I had a very large and quite stable power transformer that I used to step donw the voltage from 220V down to 110V. Even so, the amp fizzled out after about 18 months. The amp still turned on, but made strange noises in the background that made me think that the uprocessor had problems (this was a DSP modeller amp). This was after I had already used the amp in Canada for 8 years with zero problems. One possible explanation is that the power transformer was sending in a transient spike of voltage that well exceeded 110V, occuring when I turned on the transformer. I know for sure that the transformer does indeed have transient spikes on power up, and maybe over time this broke down something in the power supply chain or even down to the processor in the amp.
So in hindsight, if you must use a 110v amp in a 220V country, then unplug your amp from the transformer when not in use. Turn off the amp first, unplug the amp, then turn off the transformer When you power back up, turn on the transformer and wait a few seconds. Then plug in the amp and turn in on. This way you should avoid most or all spikes from reaching the amp's power supply circuit.