I have been doing a lot of MIDI (software synth) and guitar line recordings through a Tascam US-122 external sound card without glitch. Come recording with an XLR-attached microphone, and the signal in both Logic 5.5 Pro and Adobe Audition 1.5 is frustratingly low, so that I need to go hard right on the US-122's gain (inevitably giving plenty of noise and STILL not reaching the same levels I was attaining with a guitar line).

Can anyone help?

I am using a Shure C606 dynamic mic and the OS is Windows XP. Be happy to provide further specs if you think they'll be useful. So far I the only solutions I can think of are:
- add a new pre-amp to the setup (will a cheap Behringer do?)
- invest in a more expensive mic
- pull my hair and curse at the sky in some twisted manner of rusticism