Passive pre-amp/Quicksilver Mini Monos

Since it appears you run only the digital source, consider a more upscale CD player with variable tube output. Think of that as a self-contained CD player and preamplifier.

I have a couple of these sort of CD players, and often go that way. You reduce components, clutter, connections, and cabling without having to worry over a potentially weak in the knees passive preamplifier

I'm currently using a Schiit SYS with mine, and the sound is clear and competent. Far from the last word in dynamics or tube "magic." 

My original plan was to use the preamp section of my Grommes PHI-26 to feed the minis, but it had way too much gain, so I picked up the SYS as a temp measure. 

I own a Luminous Audio Axiom, Walker Mod, 3 in, 2 out, single ended remote unit. Never heard as much subtle, but yet dramatic, pieces of musical and spatial information contained in my recordings, until this. Incredible. HNY. Enjoy ! MrD.