I personally prefer separates, but definitely a tube preamp.
Sell the Luxman and get a tube preamp (Aric Audio Motherlode $5,500, Don Sachs/Lynn Olson Raven $5,500 (sold by Spatial Audio), Backert Labs Rhumba Extreme 1.4 $8,500, Supratek Cabernet $4,000 to $6,500.
Add the amplifier of your choice (Audio Research, CODA, Audio Research, Gryphon, etc), and you will be on your way. For disclosure, I own the Aric Audio Motherlode XL (with XLR connections), with CODA S5.5 class A SS amplifier and an Aric Audio Transcend EL34 "Push Pull" amp