Hello Marty: LA-100 is from "stone age". Today, I believe, the best Jud preamp is LA-300ME and so said Harry Pearson in July 2010 issue of TAS. He gave this preamp "2010 HP Editor Choice" Award. He called it "most romantic" - of course without coloration.
In contrary to Joule-Electra where all preamp (with pssible exception of LA-150 Mk1) are slightly romantic - ARC preamps are not consistant and vary from model to model. I am not familiar with LS25 but I listen to Reference 2; no comparison to LA-300ME, on my very subjective opinion.
I like LA-150 Mk2 too but "300" is better
In contrary to Joule-Electra where all preamp (with pssible exception of LA-150 Mk1) are slightly romantic - ARC preamps are not consistant and vary from model to model. I am not familiar with LS25 but I listen to Reference 2; no comparison to LA-300ME, on my very subjective opinion.
I like LA-150 Mk2 too but "300" is better