Upgrading my Rouge Cronus 11 to what?

Try tube rolling the small signal tubes. I had a CMII and with the right tubes it was hard to beat at any price as long as your speakers are somewhat efficient.

12AU7 single tube- Amperex Bugle Boy Holland Low Noise.

12AX7 Amperex 1950s long plates.

12AU7 Back Row RCA 5963.

See brent jessee audiotubes.com.  he will screen for low noise.  

Going from Rogue to VAC is a reasonable progression - I’ve done that myself. The VAC gear generally has a much more beautiful romantic midrange, more holography, and more refinement. Where you might lose some "impact" is in the bass and dynamics department - that’s Rogue’s bread & butter of its tube amps. VAC bass can seem a tad soft and sleepy by comparison (system dependent too). Also VAC is much more expensive per Watt.

The Rogue gear is very responsive to tube rolling, and you can absolutely extend your enjoyment through that. But you’ll still never get a midrange quite like a VAC. As far as tube rolling VACs - proceed with caution! VAC components are extremely carefully voiced by Kevin Hayes for the STOCK tubes (a skill he’s gotten better at over the years). You can get in trouble trying to "improve" on that - then a few months later you pop back in the stock tubes and realize it was much better that way (I’ve been here, many times lol). It’s not impossible to improve, but it’s easier to go backwards than forwards when rolling modern VACs. With Rogues, you can pick pretty much any random tube and instantly improve on the stock set lol.

The 170iQ integrated is a nice choice. That IQ bias is wonderful (I have 200iQ monos). I still remember many years ago hearing the older 170 driving then-just-released Magico S1 (Mk 1) and being pretty blown away how enjoyable that simple little setup was.

I agree with other gentlemen that tube rolling made a huge difference in Rogue.

Amperex ECC82 and Telefuken ECC83 is my favorite tubes in it.

After tube rolling with cost of around 400$, it is a very good value.

Thomas

With that budget you can pick up an awesome integrated. Depending how much power you need. ARC has a nice tube integrated. 

Also…SS units…Something like Pass Int-250 or Luxman 509 or 590. Next level. Huge step up! And no hassle with tubes. 

Oh and IMO no tube rolling on CMII will get you to that level. 
 

Another option is to look into separates if you insist on tubes in example, a used Audio Research Ref5 or Ref5SE tube preamp. Pairing that with a good solid state amp like Pass Labs (Class A or A/B) or even ARC’s own Ref75 tube amp will give you what you are looking for. 

I went from a Cronus (which I liked) to the Anthem STR. Superb in every way.