I had the Yulong D100 MKII...but it was before I had my T1. I had a Denon D5000 at the time and it was solid with the Denon...but the Denon is a highly sensitive 25 ohm headphone. I did preview an LCD2, an HD800 and a HE500 with it. In my opinion the Yulong struggled with all of those. It had enough beef to get sufficient volume but couldn't bring out the potential and nuance of any of these headphones. I think it would make a great DAC to pair with the T1 but from an amp standpoint I think you're barely getting there.
Best deal on T1's is at the link here. Why go used when you can get it brand new with an additional year added to the normal 2 year Beyerdynamic warranty. I got mine here and it has performed flawlessly and the people were great to deal with.