Been there, done that. As much as I'm very nerdy about gear, endless tweaking led me to change my habits and buy simpler pedals, and simpler stuff in general.
I already have a preamp, a SLO MkIIIS, which has both AUX in and headphones out (like the Big Head), plus cab simulations, it's tube driven etc. Due to practicality, I've put it into my small pedalboard and use a couple of other effects into its send/return, so I prefer to leave it just there.
I'm looking for a super small headphone amp to practice anywhere in my house or outside, possibly battery powered, with a decent EQ and crystal clear tone. That's the tone I want for practice, it must be clean.
I'd also like to use it as a preamp into the Line In or FX return of any amp I borrow for rehearsals. Does it work good?
I wonder what happens to the DI out on an amplifier when you bypass its preamp and use an external pedal. Does the XLR out works?
True. But I've read the Big Head works good with guitars, keyboards, drum machines and other devices.