I was deciding on whether to sell my AHB2 tonight, so I hooked it up to the Holo Serene preamp and the Benchmark DAC3B. I put it through the RAAL T1-1b amp interface box and listened with the RAAL CA-1a headphone.
That fatigue I had on the NS5000 system with the AHB2 is not evident on the phones. A very surprising result. I am keeping the AHB2 for the RAAL, since it sounds so good. I am even using a silver headphone cable from RAAL.