Matching a preamp with a different brand


What are some the specs to watch out for/or match to insure compatability. Too Many opinions out there on the web.
Thanks, Orlando
ojamio
Thanks Atmasphere, I just read about a BAT amp matching up with other preamps brands challenging.
I've seen BAT amps used with many different brands of preamps. But why not consider a BAT preamp? They make some nice ones in both tube and SS.
Assuming an active pre-amp, mostly just making sure both share a common physical connection standard and following the 10:1 impedance rule from there. The fun all starts from there. No two combos will sound exactly alike, but at least you have done what you can to help assure they get along together as best possible.