I have owned the AN 3.1 and 4.1, but found the best sound with a CEC TL-1 transport. I tried a Mark Levinson, Ensemble AN and toshiba transport with no meaningful improvement to justify the high cost. The CEC however, elevated the digital to a new level. IMO, the 3.1 with rolled tubes was better than the 4.1 which lost some of the relaxed presentation I had with the 3.1. You need the right power cords and digital cable. I used Purist dominus with fluid.
At the end of the day, I downsized my digital and put more energy into vinyl, which was clearly superior.
Louis