if you're not powering planars, and want a quiet high end amp, two models come to mind that are incredibly good with the VC. First is the Decware CSP2 or CSP3. They don't come along used often but if you see one, grab it, it's good. The second amp that comes to mind is the Kenzie by Ampsandsound. It's Justin's quietest amp, and is an excellent match with ZMFs. I doubt you'll see one for cheap, but if any used DNA amps come up, also killer amps. I had a used Sonett 1 and it was really nice. Dead quiet with a nice tonality.
If you're looking at cheaper options i'd strongly recommend the Feliks Echo (either gen works fine). I have an Echo MK2 at work and it's excellent with my ZMFs and Focals. Very quiet, and sounds really sweet and euphonic. Not in the same performance category as Decware, Ampsandsound, or DNA, but at many times less the price, you can't complain.
Tubes can be a pain in the butt, but once you get used to them, it can be hard to go back to solid state. completely preference driven of course. i resisted tubes for years but once i took the plunge, i stopped using solid state.
