ARC LS15: did they ever use Mundorf MCaps on it ?

HifiGeek, you have all my respect for your knowledge of Audio Research gear. If I recall correctly you are one of their official off-factory repair depots. I sincerely hope you dont view GNSC's cease of operations as a one less competitor. Huntleys mods are expensive. But for many of us it sure beats paying big $$ for trade arounds.

Thanks for your wishes, but meanwhile several people tell me that even the LS16 would not be that great improvement over my LS7 and suggest me to go straight for a 22 or a 25 without caring for the... numbers in between (14,15, 16, maybe even 17).
wow ! confusion !
anyway, I guess I'll take some time to think it over and make up my mind.
thank you all.

Best of luck to the OP.
If you like the Audio Research sound, not to mention their great support (we here are spoilt by the excellent support from Leonard in the past and now Kalvin), then perhaps saving some $$ and jumping up to the reference series will save a lot of $$ lost in incremental trade ups.
LS22 / LS25 are balanced design. Do you use balanced cables from source to power amp to take advantage of that?
Yes they will work with SE source and power amps connected with RCA but yo uwouldnt be taking advantage of the design.
They are very dynamic sounding but overall not my cup of tea.

Both versions of the LS15 sound different than the other, the LS25 and LS25ll are also different. They all have different sounds, not simply better or worse. None are worth buying without a listen.

Johnsonwu yes I am one of Steve's official repair depots. I've known Steve for a very long time. He is a friend. I also do mods but we never 'competed' for business. We all have our niches.