I need help

I have a roland quad capture that i got recently. I DI'd my guitar and got a good sound... I played around with it and had great results, but today I decided to see how a mic would sound so I plugged in a sm58 and the volume was really low I had to crank the preamps about 90% before I saw a little signal... I also had a dri100 laying around that I plugged in and put it to my guitar amp cranked pretty high and still got a weak signal... could this be the interface? I do have a direct xlr output on my acoustic that I plugged into the interface and it sounds fine so I know the cable is good...