Using an Mbox 2 Pro with external Mic Pre?

[gsguitarest]

Hey guys,

I recently bought a Focusrite ISA One preamp for my sm57 to record guitars with. When I try using the sm57 going straight into my Mbox 2 Pro (through XLR obviously), I have to crank the input level of the mic almost as high as it can go. I don't know if that's a common problem (or if it's a problem at all), I would still get a good signal out of the mic once I crank the input up. The sm57 is only 1 inch away from the speaker, and the cab isn't exactly quiet when Im getting an input level for the sm57 haha.

Once I bought the ext preamp, I plugged my mic into it (XLR to XLR) then from the preamp into the mbox 2 pro (from XLR to 1/4 trs di input, to bypass the preamp on the mbox 2 pro). With the input level on the mbox at 0, and not turning up the input of the mic on the preamp, the signal is peaking in PT. At this point I'm confused, I shouldn't be getting any signal at all with the mbox input level set to "0", yet it's peaking?

I tried going in through different inputs on mbox (input 1, input 2, and aux inputs), but I still had the same problem. Does anyone have any friendly advice on my situation? Thanks guys!