I own an LS 25 mk1 and sometimes find that it tilts the sound a bit to the "dry" (rather than "bright", per se) side, depending on the character of the the balance of the system. Relative to my Joule preamp, for example, the ARC sounds a fair bit less tube-like thru the upper registers. If the Pass leans that way, too, it's possible that the combo could sound a bit bright/dry/analytical for some tastes.
Just one more data point for you to chew on.
Marty
Just one more data point for you to chew on.
Marty