@pureclarity I also have a Belles Soloist 1 integrated amp and it is one of the less successful combinations in my system. The sound is too stressed, with no sense of power and body - compared with the Vincent or the Naim combo. Also the Belles gets too hot.
My goal is to tame the highs on the LRS+ without any changes, just by adjusting the position in the room and playing with the resistors.
The design of Magnepans (that comes from the factory) can be improved, and it is very easy to point things that can be improved on the crossover, binding posts, fuse holder, etc… but there are many user that have them playing great without any changes to those parts. So that is my benchmark - the stock LRS+ - and is that speaker that I want to improve in a “passive” way.
What is you Belles model and what speaker cables are you using?