I have a clip of one of my songs using the X-72 with my Bluebird mic for vocals here: http://www.shopofolives.com
It's a 24-bit WAV. It's been "Ghetto Mastered" upon bouncing.
I just got the X-72 and haven't had a chance to REALLY play with it, and just threw together a take that is "OK". My goal was to get a condenser sound that wasn't too harsh in the high frequencies. Both my Bluebird and Studio Projects C-1 have always had exaggerated highs that add that annoying "tizz". The X-72 smoothed out those mics a LOT, but being cheaper LDC's, you still can't get rid of it completely. Oh, and I think I had the x-72 gain up pretty high, in hopes that the transformers would do some extra "smoothing".
So far, I'm in love with this preamp. It instantly sounds "processed", and EQ is mostly unnecessary.