PreSonus Firebox varying mic levels

[kechari]

hi, I'm new to this forum. I'm running an AT4040 condensor for vocals, and get fabulous sound and levels in first channel of my PreSonus Firebox.

but in the second channel, I'm running a Shure 57 mic on the guitar, and with the pre-amp level pinned to 10, my level meter barely jumps.

Any ideas?

michael