Did I damage my speakers?

Group,
Need your expertise: I own a pair of Vienna Acoustics Beethoven Baby Grand SE's.

I recently paired them with a new-to-me set of Bel Canto REF600M monos, which replace a Bel Canto REF500S dual mono stereo amp. My preamp is a Bel Canto Pre3VB with the battery power unit.

This weekend the tweeters and upper mids, vocals (mostly female), piano,  sound hazy, at times somewhat distorted, grainy. My listening level is typically between 60-75db. I don't push these speakers hard, but I'm also getting acquainted with an amp now giving 100wpc more than I'm used to. Recently I may have pushed these speakers a bit too hard, getting up into the 80db range a few times. Could I have over-driven the tweeters with this more powerful amplifier?

I've owned the REF600M's for about two months; until this weekend, never heard this kind of distortion/congestion at the top end. Doesn't happen on everything I play (mostly CD's). Before this weekend the sound has been wonderful.

I've had these speakers for almost 7 years and have never noticed something like this before.

Wondering how to troubleshoot this.

Thanks in advance for your insight/perspective.

J