B&K harsh sound

Without knowing more, I'd suspect that the B&K amp you auditioned is not functioning properly, and needs repair, or perhaps there is a propblem with the speaker cables you are using. There are some amp / speaker cable / speaker combinations that cause oscillation in the power amp, which may be heard at a bright, ragged edge to the sound. There was a lengthy thread here on A-gon about 6 weeks ago about Alpha-Core Goertz speaker cable sometimes causing amplifier oscillation. If the oscillation is severe, the amp will overheat and may even shut down. Does the B&K amp overheat? If so, it may be oscillating.

Most of the B&K amps I've heard over the years have a smooth, relatively mellow sound, not bright as you describe. I think the B&K 1430 is the 3-channel version of the 1400, which is a decent sounding amp. In this situation, I'd be inclined to suspect the particular amp is the culprit, and not the B&K "sound" as a brand. If anything, the B&K "sound" tends toward a bit of warmth in the mid-range, and slightly rolled off in the lowest and highest frequencies.

I own a B&K receiver and have listened to Monitor audio speakers. I would suggest that this is not the best match. I found Monitor speakers bright and constricted even when played through a Pass Labs amp. Be aware the B&K is still solid state and a bit dry at the top. I try not to use any cables that add extra detail and use other components that are known to be smooth and musical. B&K makes great gear, but great systems are about synergy. I would rather build around the front end and amplification instead of around the speakers. It's just MHO.

All B&K amps I've heard are laid back, sometimes too laid back.. What cables are you using? Post the info & you'll get input from experienced users here....

Sounds l;ike a speaker cable mismatch.I just had one with CJ MF2500A and Kimber Monocle XL cables.That sound hurt my ears and i thought the amp was broken.Then i tried a number of cables and stayed with Harm.tech.cables.

I've heard B & K with Monitor Audio speakers, nothing wrong with that match.
I'd suspect other things. A bright room, a malfunctioning amp, etc. You've gone from 60 to 200 amps and to my ears, B & K is a little warner sounding
than Rotel -- the extra power may be bringing something out that clashes with the room or with your ears. You may also be playing the music louder
than usual, which could cause problems in the room that you didn't encounter with the weaker amp.