I have done it on a number of occasions, both a CJ Premier 17 and Karan K180. It is doeable and I had the voltage changed in the UK. The CJ ewas easy, they are built for both markets. It is simply a matter of changing the taps on the transformer, to change the voltage. Likewise the Karan
I tried it for a Viva Solista tube amp, not so good. The US voltage was doubled to what was then the European standard 220volts, not the UK's 240+, after blowing several caps, it had to go back to Italy and took a year, to have UK specifeied transformers. An expensive mistake.
The answer is then, it depends on the amp. Some are OK, some not. Tube amps seem more of a problem, perhaps because of the large plate voltages in output tubes
I tried it for a Viva Solista tube amp, not so good. The US voltage was doubled to what was then the European standard 220volts, not the UK's 240+, after blowing several caps, it had to go back to Italy and took a year, to have UK specifeied transformers. An expensive mistake.
The answer is then, it depends on the amp. Some are OK, some not. Tube amps seem more of a problem, perhaps because of the large plate voltages in output tubes