Japanese Luxman Integrated Amps

Any japanese (or other) 100 volt device can be played in USA using a small voltage 120/100 transformer: transformer plugged into 120 volt wall socket, transformer's outlet out: 100volt.

this one will work either 120 to 100 or 100 to 120

you don't need some big thing, these do a great job.

Warranty is void for sure, as shown a good transformer is over $1k

better off sticking to U.S , then another Big issue especially as of last 2 years customs duties and big time damage issues and refusal to pay on claims I know several people who got burned ,even banks refused to get involved .

Luxman USA warranty policy

I brought a used Luxman 590AXII and love it, but I brought it in the US with 120V. As @audioman58 and others stated, there is risk not just in buying it, but in selling it. I doubt you'll save any money in the short or long run.

I've not heard of any 'software' for their integrated amps, maybe for their DAC's? 

I used a step up trannie for my Luxman CD D06u without loss of anything...it was simply perfect. I sold them both as a package and the buyer loves them too...