Luxman L-509Z Integrated Amplifier

Get a step down transformer.  Aside from wasting a bit of electricity it won't impact the sound quality. If anything it may actually help smooth current to the amp and add a layer of protection against an electrical surge. 

Wow! That's a $5000 difference! I wonder how much Accuphase is in Japan?

It's crazy right ? :) That's what I think too. I mean I understand some markup but not almost double, that seems like a ripoff :) 

@perkadin thanks for your response. Interesting as the dealers on ebay offered to include the step down transformer. But according to Paul McGowan of PS Audio he says that the transformer needs to be good quality and at 10x of the required power (which is pretty impossible to do). 

Do you have any suggestions on quality transformer brands ? 

Paul probably means 10x continuous power, not peak power.  The 507z draws 86 watts at idle so using Paul’s math that would be about 860 watts for the transformer.  Another recommendation I’ve also heard that you want at least 2x peak draw, so in that case the 507 has a peak consumption of 350 watts which means you’d need at least 700 watts for your converter. I don’t have any brand recommendations but power converters are not complicated devices, and everything is made in China anyway so I’d probably get a generic model off Amazon with 1000 watt+ rating just to ensure additional margin of error for exaggerated ratings.  You can find them for less then $150 with your choice of Toroidal or El designs.