What kind of interconnects are you using? What kind of power cables? Speakers? Amps? There is a level where the resolution/transparency of the interconnect/preamp/amp is not enough to show differences between DAC sources. There are absolutely differences, but you may not be able to hear them with your current equipment/cabling.
That being said, it may be that there is not a huge difference between the two DACs you are auditioning. Based on what I have seen on the Aurender A10 internal architecture, I would think the Aurender would have more resolution.
I think you're also using the Aurender as a preamp here? This could be driving a lot of the sound signature.