Cartridge incompatibility, Soundsmith and Luxman

Cardas Clear Beyond sounds amazing, but they're not inexpensive...

Cut the cables in half, add 2x extra terminals and put the SUT in between?

There seems to be one easy thing to do and many crazy solutions. Umm.....please don't take the top off and modify or tweak your amp. There are a zillion excellent cartridges. Buy the one that fits the phono stage and have a great time.

Changing the phono load resistors is neither a mod nor a tweak in my book. But why do you hold the opinion it shouldn’t be done?

Finding that load resister is not hard. It will be right off the phono input @retipper has already joined this conversation and is obviously loath to give himself business by making this suggestion but, I would suggest acting as an obvious shill for Soundsmith that you send him your amp and he will be happy to make that modification and sell you some loading plugs for a very reasonable cost.

How does the Luxman sound when playing other sources, such as CD player or streamer, as compared to your prior rig?  It would help to know if the basic sound of the Luxman is to your liking.  If you like the sound, then it is the phono stage that is an issue (either not very good, or incompatible with your particular cartridge or other aspects of your set up).  How much have you experimented with other aspects of your phono setup--have you played around with VTA, for example?  A higher VTA (pivot of tonearm elevated more) will tend to shift the tonal balance more toward the high end.