Talking about a preamp. I have multiple sources (turntable, DAC, physical disk player) and need a variable output to go to my speaker amp, plus a fixed output to go to whichever headphone amp I have hooked up.
I currently switch between two preamp/line stages - a Burson Conductor Virtuoso and a small DIY passive line stage. My biggest issue with using the Burson as a preamp (I don't us its DAC) is that it lacks a fixed output, so I can't use my Valhalla or the ampsandsound Mogwai I've got on loan. My DIY passive has two switchable outputs, fixed and variable, to feed both speakers and headphone amps. Only issue with the passive is it lacks a remote, which is handy when listening to the server on shuffle.
So, I am hoping the upcoming Schiit preamp will support external headphone amps via a fixed output, maybe even multiple fixed outputs to support more than one headphone amp at a time.