new marantz sc7 and sm7 system I bought from Japan in 1979.

To add to what Rodman said, what voltage are they?  If not US, they will need a step/up transformer.

I bought these from Tokyo's Akihabara Electric Town.  These were built for US market and are have adjustable voltages for multiple countries (110v to 240 volts).  They have the US electrical cords.  I have used them with US and European voltages. These are the Gold Anodized versions.  They are awesome when the system is setup.  I bought a set of the big Pioneer speakers from Japan also along with the Top of the line Pioneer PL1000 turntable that has also been boxed since 1982.  I have many other vintage stereo electronics that I purchased from Japan that are also in mint condition.  Dynamic Range expanders, equalizers, Teac tape decks, akia reel-to-reel tape decks, All are with original papers, manuals, and boxes.

You,  "...have used them with US and European voltages." and they're still, "brand new"?   Neat trick!  

So why don't you list them on the marketplace site instead of trying to back hand sell on the forum? And without having this stuff serviced, I say it's all worth the current price of scrap metal...

Thanks for you opinion but I just want to know whats it's worth.  I don't plan to sell any of those items.  I would always keep my possessions no matter what.  I plan on taking them out of the boxes soon and get a cabinet that will hold all of the items because they are very heavy and I have many pieces of stereo equipment.