Buying a Luxman L505z from Japan

I bought a Luxman 507uX II that needs a step down transformer but I bought it used, not new.  I don’t know what a brand new one would sound like but this unit sounds great!  I think that was your main concern.  This is coming from someone used to good equipment sound.  My last integrated amp was a Pathos Classic Mk III feeding a pair of Sonus Faber Sonetto II’s. About warranty and repairs, that’s another thing you’ll need to consider.  Enjoy, you’ll love it.  

Your net present value calculation is wildly different if you expect to own it forever, vs. for 5 years.  If the latter, your resale value on the Japanese version is way lower than on a U.S. dealer, manufacturer-warranted product.  

Buy a North American unit. Why waste time and effort with potential SQ and repair issues.

Has anybody ever used a bucking transformer to step down mains voltage?  If you’re not familiar with these, a the primary of a auxiliary low-voltage power transformer is connected to the AC line as expected, but the secondary is wired in series with one leg of the AC feed of your amplifier. An 18 volt secondary connected in this way will either drop the AC feed by 18 volts or raise it by 18 volts depending on the polarity of the secondary series connection.  Schematics are plentiful on-line and are cheap and easy to build. I have been using these on vintage tube amplifiers successfully for years to drop my 123 VAC house voltage down to 112-115 VAC as that’s what the original design of the vintage amps called for.  Don’t try to run something like a Dynaco Stereo 70 straight from your mains if you don’t want to pop a filter cap or red plate the output tubes!  These bucking transformers put out little heat when in use though I do try to match the secondary ampere rating to the current demands of the amp in use - ie, a 3 amp secondary ampere rating is good to 360 watts.

Transformers definitely have an impact on sound and performance. You don't get the original manufacturer warranty either. I am considering an Accuphase amp and did research on different options. Will definitely not go with the Japan version. Not worth it for me anyway.