Recommended integrated amplifier for upgrade

Of course, McIntosh is the answer with Sonus-Faber. Integrated, I would look at the MA-2275. Not easy to find but a work horse of an integrated amp. No issues after 15 years except for tube change and a simple dial exchange.

Try a Naim Supernait. I have the original version and I’m very pleased with it.

I’ve had McIntosh solid state - not impressed, however I just got into Cary Audio Sl1-100. Holy smokes. I’ve got the Wow I’ve wanted with every aspect of music listening. Project turntable and vinyl amp, audio lab600 cdt and Schit dac. Raven Corvus monitors and 2 13” subs. Even the wife is gushing over the sound. 

+1 for the Coda CSiB Integrated.  I have had mine for 2 months now driving Thiel CS 2.4s which present with a wicked impedance curve (around 2.8 ohms at 600 hz), and the Coda handles it with ease.  I have the v1, 150 watts per channel into 8 ohms with first 18 watts in class A, power doubling down as you halve the impedance. I couldn't be happier.

I have not tried but a Hegel should work great, H190 or H390. Bryston B135 cubed is also great.

SF used to require a lot of power and if that is still the case I would avoid class A amps. Class D may be a great match. The Rogue Sphinx is for example a tube plus class D combo.