Suggestion for best stereo amp ?

SS go with an FM Acoustics or an old Harmon Kardon Citation XX.

For tube find an old Lafayette KT-550.

These should solve all of your upgrade wants and needs.

Happy Listening.

@kalali
@mzkmxcv 

Totally agreed with kalali. You nailed it real good. mzkmxcv always thinks that measurements (numbers) define sound quality or is an absolute gauge to define sound quality. If that's the case we all would have had the same gears in our racks. Come on.....Get real! 
This hobby is about listening and enjoying to the music we love, it's about listening and how we perceive one setup or system sound and performance according to our ears. 

Pierre:   

Sounds like you enjoy the sound from the Krell/Wilson combo. The problem is not with your setup it is with your other half.

I have long been a Krell/Wilson listener and truly believe that you might regret a move to lesser (more acceptable product). 

Holidays are coming so consider that you are in a good leverage position.  To swap out gear will be costly and ultimately you might not like the results. How about keeping the sound system as is and make an investment in some Diamond stud earrings for your wife.  Ask nothing in return but that she tolerate your stereo problem.

This way everyone wins!   

Happy Holidays!
Perfect_sound  

Consider the Naim 500 with the 500DR power supply.  It is incredibly natural sounding (especially when paired with the Naim 552 pre-amp).  The 500 is fast and powerful.  It is essentially two mono blocks housed in a single box.

Krell recently upgraded their line to “XD”. From what I’ve read its been well received.