How to change Krell S-1000 voltage for Europe

It will need to go back to Krell.

Thanks.

You should be pre-warned, many hi end audio companies will refuse to change voltage in order to protect overseas distributors against various currency fluctuations. This prevents Europeans from buying North American gear at a lower cost or vice versa for some equipment, better to check first.

Krell does just tht but will do it for the original owner

The amp needs not only rewiring, but also uploading a new software to work on 50Hz AC mains.

One option is to buy one of the older PS Audio power regenerators. These can be set to input 220V/50Hz and output 110V/60Hz. The other option (I have done this twice with an old Krell HTS, I was not the originally purchase either) is to have Krell convert it for you. I believe Krell charged me 300 euro in France and they did the conversion for free (?) when I returned to the USA.