Dear @audiojan : " need to go down the route of an SUT. "
Well, due to what you have in the Luxman that’s the bad move ( is up to you. ) that degrades the higher the cartridge signal against a " simple " internal modification below Luxman advise. Maybe I have to say SUT is the wrong way to go for the quality level of the cartridge you own, can’t benefit you in anyway but the other way around but as I said: is up to you.
" there is no problem to replace the 100 ohm load resistor with a 470 ohm load resistor. Any skilled technician can do that. I would do that way before throwing either baby out with the bathwater. "
R.