M AUDIO DELTA 1010LT with a marshall TSL using XLR silent

Hi everbody, first post

I have recently got into cubase sx 3 and enjoy using it to record my band. I plug a microphone into my onboard sound card and press record.

I have just today won a bid for an m audio delta 1010lt for £87 inc p+p second hand (good deal?).

My 100W marshall TSL jcm2000 guitar amp has an "XLR" output on it. I wish to be able to use this with my sound card. Is it possible? Iread something about a preamp built in to my microphone (same as XLR?) sockets. Would i need to turn this off?

Also for listening to mp3s ive seen people plug there outpout straight into stearo speakers without a need for an amplifier, he said they were studio monitors!! no amplifier!!

Thanks guys, my main issue is recording from my marshall to cubase wirth XLR because i can then do silent recoding.