low input volumes :(

The Mbox mic preamps are perfectly good, capable of great sounding tracks. What microphone are you using?

you will probably need an outboard pre amp to match the impedance of the ribbon mic.

Interesting, I've never seen any Neumann ribbon mics. Assuming you do have a ribbon mic, the Mbox preamps are not really appropriate, since they only have about 40db of gain. Ribbon mics have very low output.

You will want to look for 60-70 dB of gain from the pre that is working with your ribbon's. You can also daisy-chain two pre-amps for a dual stage pre-amp stage, for additional boost when working with preamps with lower gain ranges.

it worked well when we threw on a XLR-to-TRS converter, and then switched the input on the MBOX to instrument. it still didn't sound as grand as a $2000 ribbon mic should.....ya digs, and i know its not the mics fault

Why do you persist with the Neumann ribbon BS? There is no $2000 Neumann ribbon mic. Annyway, if you've got a Neumann mic plugged into the TRS input, you're doing something wrong. If you can't get it to work correctly in the mic input, you're doing something wrong.

Since you were using a condenser, thinking it was a ribbon, perhaps the absence of phantom power was causing the low level. Most likely not the issue, I know.