Ok, I have a Line6 POD (Not the 2.0), and a Delta 44 card. Well I am wanting to run the POD at +4 balanced, and accorind to the manual of the POD that shouldnt be a problem. So I plug in my TRS cables from my POD to the 1/2 in on the breakout box of the delta, change the delta to +4. And the best signal I can get is like -15 or so, that is with all the volumes cranked on the POD. I cant figoure it out at all.
I don't own a POD, or have easy access to a manual, but my "gut" and experience tell me that unit is not going to put out a true +4 dBu signal, which is what your Delta is looking for in +4 mode. Why do you need it to be +4? What's wrong with connecting them at -10 dBV anyway?
Try switching your Delta to -10 and you should be fine.