Will a Rogue Audio Sphinx v3 perform decently with my Sonus Faber?

going from incredible boXem to a middling tube amp doesn't make sense imo. get a solid stage integrated. the A-50 from Onkyo fits the bill and is a much more potent device as a whole with DIRAC DLBC

It will do nicely.  Good choice!

I have known this integrated quite well for the past five years with speakers even less sensitive (Magnepan and KEF) than yours and a bigger room.  I have also auditioned the Lab12 pre just a few months ago in dealer’s listening room. 

In a room your size you should have plenty of power to drive your SF’s to sane listening levels.  I typically play music at 75-80 db’s (A-weighted) and this was absolutely no problem for the Sphinx v3 (non-Magnum).  On rare occasions if I were listening to something like Tool and pushed it up to 80-84 db’s with the Sphinx, it would handle it quite nicely yet  85-87 db’s (again A-weighted), the soundstage would be effected negatively in my fully carpeted room; more so with the Maggies than the KEF’s, yet still noticeable. 

With a real solid DAC the soundstage at those more sane stated listening levels was really, really nice.  I had heard the Lab12 at a dealer and it too was a very nice performer.  I am going the other direction than yourself with a full separates (no phono needed) set up and I did not feel compelled to purchase the Lab12 as I was looking for a significant step up in musical reproduction.  As great as the Lab12 sounded, my thoughts were it would not provide enough in the upgrade path as I was seeking.  So yes, with a real good DAC you will get very close I believe to your current setup give the considerations noted, with the Sphinx v3.  It served me well for five years.  

I had the V1 of the Sphinx and found it a bit cool sounding, though SF speakers, might balance that out with their warmth. I suspect it has also been improved from V1 to V3. I have not heard the doubt that it will drive your speakers just fine, but I would also look around at other integrated amps. And keep the DAC separate.

Of brands I have experience with, I think the Musical Fidelity M6si would be good, and I am a super fan of Audionet, the SAM G2 might be a fit for you. Lots of used options on these.

may thanks to all!

@zlone i didnt even know audio net, will keep an eye. DAC will indeed remain separate for now. Manunta Eco3, with LPSU, not well known but i found it excellen for the size and price i paid, t and sold my (even better) Audial S5.

@swaudiofan great to hear your own lab12 experience! may i ask what the power amp was? was it lab12 all the way?

@kofibaffour yes i see your point but the Sphinx has class D power section, and i now have tubes in my pre, so in some ways similar. That Onkyo looks good value but will keep DAC / streamer separate for now. I guess you have hear the Arthur? not many have! i found the clarity and lack of distortion at high volume incredible but i can't play loud too often sadly 

@rar1 yes i have chord odyssey cables so should work , and good to know Rogue people are helpful! There is a dealer in the UK with a good reputation but 300 miles from London!

@mapman thanks!