seems you can buy a new 509z for $8,500 plus shipping
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2047675.m570.l1313&_nkw=LUXMAN+L-509Z&_sacat=0
used ones and other slightly older models (even new) are also listed below the 5 new Z models.
meanwhile, the earlier 505 are listed for $2,800 new, and there are several models in between.
I would research the model’s reviews, feature differences.
Power: it takes double the wpc to make a +3db increase in volume, so the difference in 505’s 100wpc and 509’s 120 wpc is insignificant.
I’m not pushing the 505, just using it for example, Personally I would buy the pair I found and jason liked
https://reverb.com/item/67940102-luxman-amp-pre-amp-m02-c02-1980-d-gray?gspk=SGlmaXNoYXJrLVJldmVyYg%3D%3D&utm_campaign=Hifishark-Reverb&utm_medium=affiliate&utm_source=partnerstack-legacy
hifiengine has manuals
https://www.hifiengine.com/manual_library/luxman/c-02.shtml
https://www.hifiengine.com/manual_library/luxman/m-02.shtml
here it is with the 3rd piece, tuner
https://www.usaudiomart.com/details/649977063-luxman-m-02-t-02-c-02/
I'm very tempted, gonna measure if it fits downstairs, then sell my Yamaha CR-1020
btw, REVERB definitely supports the buyer, completely and quickly resolved two issues for me.