I really think that you must have got a defective mic as even my piece of shit Marshall 2001p sounds better than a dynamic on acoustic for the most part.I'm not familiar with the Core condenser mic that you speak of and their phantom power requirment but could it be possible that your Audio Buddy phantom supply is broken?I'm not dissing the Buddy,I have one and I love the little dude but if your Core mics are battery powered or something maybe the power supply in the Buddy is busted.Or even stupider question,what about your mic cable,could it be broken?A cable might work ok on a dynamic or battery powered mic but may not carry the phantom power to the mic.
If I were you,I would try a couple different cables AND another phantom power supply,if the sound quality does not improve, than e-mail Alan and he will take care of you I'm sure.I've heard samples from this mic and an Audio Buddy that sounded quite nice so you should be able to get good results from that signal chain.I'm a little confused by your description of the sound,first you say muddy and then you say how harsh it sounds,almost a contradiction to my way of thinking.If you want to hear a harsh mic,I'll sell you my Marshall 2001p,it should be a reference mic for a harsh sounding mic.