What DAC did you go with from Audio-GD? I happen to use the NFB 28 fully balanced DAC and class A amplifier. And one thing about kingwa is he knows how to put quality into his work for prices that we would not get here perhaps with the exception of Garage 1217, Schiit, and a few others. Kingwa really knows his stuff and putting the possibilty of 5w into 50ohms for my HE-560 really does make them sound very impressive. It took a bit to grow on me when I first got it, it uses the sabre 9018 or the like I believe and is capable of some very clean, detailed audio without the bright highs that can get to me still very detailed and transparent with a hint of smoothness that works well with the HE-560. Hell my SM64v2 from earsonic sounded sweet from SE jack but cannot find the adapter so I have been using them with my PB2/dx90
I grabbed a used NFB-2.32, which is basically a DAC-19 using Wolfson chips. I plan to eventually replace that with a DAC-19.