Let me just say I know what you're talking about. I have Paradigm Active 40's (which are self amplified Studio 40's) so my speakers are similar to yours. Same tweeter, anyway.

When I first got the 990 I also thought 'man this thing is much brighter than my old Onkyo receiver'.

But the more I listed, the more I realized something...it's not 'brighter'...it's cleaner. It's more revealing. Nothing is masked. Subtle things like the vocalists breath and the skins of the drum could now be heard. But on the flip side, it really revealed how crappy the sound on DirecTV is!

I've always felt that Paradigms are on the bright side in the first place, so I'm eager to hear your findings on the Arcam. How much does that Arcam cost, anyway?