Yeah, but what if set something incorrectly on the Kemper. I always found that the MBritt profiles sound very dull or muffeled.
I uploaded a testvideo to show you what I mean:
Yep, that's the classic lead 80 that MBritt uses on almost everything. It's good for clean to low gain, but I do not like it at all for the gain levels you're using, because it sounds dull and muffled, exactly as you describe. I suggest switching out the cab for a V30 of your choice. I use a V30 cab from one of MBritt's other profiles (Wizard) on all of his profiles with gains >~4. I've tried a few Top Jimi profiles, and I don't like them much, either.