I experimented once with the Ayre QB-9 USB DAC. At first, I was impressed with the way it sounded. I used the MAC Book Pro computer with 4 GB RAM and the 120GB solid state drive. I used the Seaport Free Agent Go Pro 500GB external hard drive to store my music files.
After several months of listening, I decided I did not like it the way it sounded in my system. In addition, there were too many boxes and wires in my living room. I sold everything and returned to my Ayre CX-7e MP CD player. I never looked back and continue to like my Ayre CX-7e MP CD player very much.
For me, I liked the sound coming from the Ayre CX-7e MP CD Player better than the sound coming from the MAC computer and the Ayre QB-9 DAC. It felt more natural, clearer and better than the computer and DAC did. I like my Ayre CX-7eMP very much. It is running balanced into my Luxman L-590ax integrated amplifier. I hope this helps you better understand the Ayre QB-9. I suggest you borrow one and try it in your system.