Just recently bough myself a preamp (M-Audio 192|4) and have been liking it so far. The only problem is that for whatever reason whenever I use the 1/4 inch headphone-in port I get a dull pain in my ear within 10-15 minutes. This never happens when using the normal headphone-in port on my pc, in fact whenever I switch over the pain seems to subside. I am fairly confident that I am listening to them at the same volume levels, if anything I end up turning the sound of the preamp lower. I do notice that the bass seems to recede a little when using the preamp so is it possible that my preamp is messing with higher frequency sounds?