Matching up speakers and amps

Based on reading about the DNA 0.5, & having one in one of my systems (with Spendor S3/5 SE's), I'd keep the McCormack--very nice sounding amp, unless you have very hard-to-drive speakers perhaps.

PS--what are you looking to do, i.e. what's bugging you about the sound now, etc, that you want to improve?

*Actually, I have no issues with the sound of my system, just that I have had the McCormack and the Acurus pre amp for 13 years and I'm itching to try tubes!*

Easiest thing: Get a tube pre-amp. Like Mechans said, a used ARC, C-J, or Cary, you could add VTL. I have a wonderful Cary SLP-98 pre-amp, but paired with a SS (C-J) amp. Depending on what kind of sound you want, you can get some pretty nice used tube pre's for $1000-ish. Want kind of "tubey"? A VTL 2.5TL, or older C-J. Pay more, like for a more modern C-J or Cary, that's a different sound. "Better", more neutral, but still will add some "tube warmth".

Tube Power amps: that's a whole 'nother issue. Make sure your speakers are fairly efficient, & "tube-friendly". I'd start with a tube pre......