Listening to the HPA-01 through TH-900 and source A&K 240. Playing DSD albums right now it's JT beautiful vocals, bass and guitars playing against a black background makes me smile and tap my feet. Favorite track is Secret O' Life. On the best of Marvin Gaye What's Going On, the sax intro to Marvin's strong vocals. Brings me back to the good old days when life was simple. On the rock side, the Division Bell, Pink Floyd What Do You Want From Me, David's guitar work and vocals really shine. In my opinion the HPA-01 makes the vocals stand out. Used the TH-900 with the voltage output. Tried the current with my HiFiMan HE-500 it does make a difference in sound. Looks like the best of both worlds. I'm happy with this buy.