Tube Amp or Tube Pre Amp

Definitely a tube preamp, with either solid state or tube amp. I have an Aric Audio Motherlode XL preamp driving: CODA S5.5 SS amp, Tubes4HiFI KT-120 tube amp, and an Aric Audio Transcend "Push Pull" EL 34 amp. The Motherlode excels driving all 3 amps, and a serious upgrade over my last solid state preamp.

Great preamps can be had from: Aric Audio, Spatial Raven preamp, Supratek, LTA, BAT, Backert Labs, Atma-Sphere....my favorites being the Aric Audio and Raven (which was designed by Don Sachs and Lynn Olson). Great luck on your search

+2 @larryi 

Amp and speaker matching is paramount. From personal experience, I have tried a McIntosh 240, Marantz 8b, and a McIntosh 462 with Cornwalls. While the tubes amps sounded nice, the 462 was on another level which your 352 should be as well. I have used a  McIntosh C22 MkV and  Fisher CX-2 with all the above. Personally, I would sell the C49 and try the C22. The C22 responds surprisingly well to tube rolling. I settled on. Telefunken ECC801S in the output, Telefunken ECC83 in the input, and Amperex ECC83’s in the phono slots. Bottom line, solid state amp and tube preamp. 
Happy listening!

Tube preamp with the right solid state or hybrid amp. Tube amps just have too much maintenance for me, especially my older ones that don’t autobias I have PSAudio BHK 300 monoblocks and also the Stellar M1200 monoblocks. My tube preamp is the stellar Aric Audio Motherlode XL. I also use a Space-Tech super rectifier. This has been audio heaven for me.

Yes......What is your budget? (add more!)  300B push-pull amps hard to beat. 

Maybe first add a pair of subs to yr. Cornwalls. As others have said maybe a speaker upgrade but the subs w/ the Cornwalls would be a whole new ballgame.

Some great brands Lamm, Spatial Audio lab, Triode, Air Tight and Shindo come to mind. (Spatial fan and user)

Also some great integrateds can be had.

Re: Primaluna EVO 400 Pre for Cornwalls. It should be noted that the rectifier tubes are late 50s Holland made Mullard GZ34’s with the metal base. A pair of these will set you back but well worth it in my experience. Also, the two gain tubes are vintage Amperex "Bugle Boy" 12au7’s. This combination of tubes takes the Primaluna to a whole new place. It can take any preamp set up for these tube categories to a whole new place.