I'm impressed that AIYIMA D03 has surprisingly high sound quality when actually used.Yeah, this is a good little amp. I have had this for nearly 2 weeks now and I am pretty stoked to say the least. I am running from my Hama streamer at either 16 or 24/48kHz. I can only tell the sample rate at this point but to be honest it sound good enough and with ease. I am using an Amazon Basics 5m digital coaxial cable so its a pure digital connection and in short, wow! It serves up a crystal clear and punchy sound much better than my Topping E30 running into my Cambridge Audio AM10. The dropout issues have disappeared so I can only put that down internet and windows driver issues, its definitely not this little amp from Aiyima that was causing the problem..
It's very similar to what I felt on D03 and what you felt.
The D03 is still unfinished as a product and I feel it is a little rough, but I think it is an amp that I look forward to future growth.