phantom mixer



with the lexicon alpha soundcard i got for my laptop (dell latitude 600) recording, i have 2 options on powering my microphone, i can use the regular phantom power adapter, or the berhinger xenyx802 mixer with phantom power build in...should i use the adapter seeing as it has no levels to adjust, or should i use the behringer to power the mic, where i would have to adjust its levels accordingly?....any help would be great