I also have one and set up side by side comparison playing a track and comparing the Saber ess DAC in the ultra by using line out. Then against my Advance Paris A10 Amp DAC (Saber ess I think) by using optical out from the Ultra to the amp. Then lastly using the SU1 attached to Ultra USB out and into an analog RCA input on my amp. I like the SU1 the most which uses the AK4493S sound much richer to my ears. I wish there were more new equipment using AKM DACs. Su1 I use mainly for my pc desk speakers. Easily the best $100 I have ever spent.