Is my new amp TOO GOOD?

My gosh this was a substantial upgrade. Integrated probably blended all your frequencies together versus separates that are substantially better.

My guess is it’s bringing out the speakers you have maybe in a different way. Maybe better maybe worse but your hearing them differently.

And the subwoofers probably need a lot of tuning because if they’re off probably the trebles gonna be impacted. I have gain settings on my amplifiers and when I adjusted them it reduced the trouble sound from the speakers. But I would avoid adjusting your treble so aggressively because you’ve really reduced it and I would focus on other areas.

Basically you’re hearing your speakers differently because the components you have are outstanding. I’m not a big fan of bell tweeters because they are very revealing and kind of annoying. I don’t even like the diamond tweeters I use on my Bowers speakers. So I’m thinking about sonus faber. Sometimes revealing may not be such a good idea for comfortable listening. 

Try different music because now you’re hearing the recording quality a lot better and because of this I am now very disturbed by the poor quality of most of the things I’m hearing because the engineers didn’t do a very good job sadly but I live with it but it does make even a bad recording sound better it’s just I’m noticing them more. Which is why revealing speakers can have their problems.

Final point, 90 dB is very very loud and approaches a danger zone and I'm not sure how big your room is. I would lower the volume and get used to lower volumes for your hearing health. You should be able to handle less volume now that you have a more revealing system.

May I ask the question: Are you using any silver interconnect cables? Silver can add a brightness to the presentation from my experience.

What jumped out as a red flag for me is the speaker positioning. 
11 feet apart is a bit much. What happens when your speakers are spread so far apart is you don’t get the midbass and midrange filled in. I have experienced the exact issue you’re describing and in my system I solved it permanently by moving the speakers closer together. My recommendation would be to start at about 7 feet measured between center of woofers. Toe in so that they cross about a foot behind your head. Listen to it and start moving them apart keeping the same toe in. I’m pretty certain that with speakers set between 7-8 feet apart you will eliminate this problem. Set your listening position to be approximately 84% of the distance between speakers (woofers). 

When we upgrade we think it’s an auto improvement? No , you have to wait till the new components settle , Be patience. When the system settle , you can slowly analyze the sound .Op even if you only change one interconnect  the sound of your system change. With the addition of new amp , you got so many changes.So slowly figure it out to match the new amp in your system? Maybe burn in is all you need.

@mojo771  I don't have your gear nor have I listened to it, but after you try some of the other suggestions e.g. break-in time, speaker placement you still find the top end to fatiguing  maybe swap the 12ax7s for lower gain 5751s.