220 power conversion to 110.

I own a DA-60 integrated amp know of a guy in Long Island N.y., he is an authorized Jadis repairman . I have root around for his name and address. There is a dealer in Florida who mighty be able to help you I suggest you do a search to find him, but be forwarned anybody who calls themselves an Audio Salon might offer what you want but the price...well... that's another matter.

Using a converter is trial and error. Depends on the converter and the area you live in. If you have very noisy power lines a down transformer may even be beneficial. However get one that is about the double in output of that what your Jadis needs, otherwise there may be some loss in overall dynamics.
Generally speaking, Jadis gear is easy to up or down convert. One will just have to resolder a few points on the transformer. Any good technician should be able to do it.
Don't know about the latest Jadis gear though.