Preamp help for First Watt F3

I'm thinking about getting the First Watt F3 to power my Zu Audio Druid MKIVs, but I've hear its a tougher amp to pair since its input impedance is 10k. I was wondering if you guys had some recommendations about which preamps go well with it? I was thinking about the Red Wine Audio Isabellina but not sure if that would work. My requirements are pretty simple, just a pre with the usual set of digital inputs. USB would be nice but not required.