It too have been on the passive-active-passive joy ride, so I know what you mean about the audio nirvana path. That is why I was especially careful and attentive going back and forth with the Lightspeed and Joule LA150 Signature. Both are great preamps (at $450 versus $6,500 that should be enough to choose the LS) but regardless of cost, I preferred the Lightspeed - a matter of taste and system context no doubt. I use it with my RM10 and RM9 Special Edition. Is it the best? Heck I don't know. I only know that it is very, very good and at $450 stupidgood (my favourite word from Bobby P at Merlin).
I do also hear - no pun intended - the listening and engineeering dichotomy. I can only say that having heard several Music Reference amps (RM10,9,9SE, 200, and 200 wired in Class A and triode)that while Roger certainly knows his way around a test bench, the quality sound of his amps suggests that he either does listen, or if he doesn't listen, it may in fact not be relevant to do so (I think he listens)and that he does not lose that skill of producing good sound with the challenges presented in designing a preamp.
None of this means that I could tell anyone whether they would prefer a high-quality tube line stage or a passive - I know I can't - but the Lightspeed produces some of the very best sound I have had over the past 30 years where I've tried scores of some of the very best preamps and amps on the market. If money is any issue at all, the LS, with proper impedance matches between source-pre-amp (gain should be no issue with most sources) is a low-cost option for SOTA sound that for some might be as good or better than anything else you might buy.