Looking for a SS integrated Amplifier recommendation going into a new system

I have the RAAL SR1a headphones and have tried a lot of amps with the RAAL. The very best by far was the KRELL K-300i.

First 90 watts in Class A. Huge bass and so smooth. Look at what Stereophile says about this unit and compared to the Boulder 866 and a few others.

Another vote for the Luxman L-590AXII. After more than 20 years of messing around with more than a dozen of amp combinations both integrated and pre/power, the Luxman beats them all for sheer simplicity in a one-box (minus extra cables) and of course, sound quality. It is high quality at a price that’s not too astronomical. I also own a Naim separates system and another integrated amp but the Luxman is the new reference that gets to stay in the main system.

Good luck.

A lot of great choice and recommendations.
I Second the Simaudio 600i recommendation and you should also look at  Belles Aria Integrated Amplifier from Power Modules. https://powermodules.com/aria-integrated-1

Well, if you’re in the market for a true end-game piece and open to used, here’s a Vitus integrated that retailed for $27k available for $11k that’ll nail all your hot buttons and you’re set even if you upgrade your speakers significantly in the future...

https://www.usaudiomart.com/details/649766445-vitus-sia-025-mki-integrated-amp/

Thank you all for the recommendations.  I am going to take time review some of the items.

Regarding the tube amp possibility, I have my share of tube amps before, but limited to just flea power category where the maximum power output I have is 8W (300B), and some even lower at 1.5 to 2W (45).  I might revisit the possibility of trying higher power tube amps, but for now, I prefer staying with SS.

Meanwhile, appreciate the inputs on other features I might need.  They look to be very useful and have more flexibility for future setup.

Good to know  Luxman 590AXII gets so many positive votes.  That is one of the choice very high on my list.