If the system sounds sluggish and the TT is spinning at the proper speed, warm up is the most likely cause. Its easy to miss diag something like that. I used to have a McCormack DNA 125, and when I first turned it on, the bass sounded like it was having trouble keeping up the the rest of the system. After some time, it just went away and everything sounded normal. It seems like everything I've had from Pass takes a while to warm up. ARC, not so much, and BAT is probably somewhere in the middle.