Nice to hear from you. Ok, the Topping D10 is a good starter DAC. Compared to sourcing the music signal from your devices' analog/headphone-outs, I'm not surprised that you hear a significant improvement.
What did you think of the Aune T1 MK3? Were you able to directly compare it with your other gear?
While I've never heard the Burson HA-160, I see that it's a 8-year-old Class A amp. While I'm sure it sounds pretty good, it's...