Recently, I got an apogee Bigben for my D2.
HAHA. In previous, I always think that digital signal is not much impact on sound quality. Expecially for an async USB.
I beleive that an async USB will be good enougth for remove jitters.
But, it seems that I am wrong. The USB is really sensitve with the player software, I means that the OS. The windows 7
is not very good. And ubuntu studio with low latency kernel sound more relax that windows.
I got a Bigben. My sound card is AES16. I have compare D2 USB input and the AES 16, the USB sound more clarity,
a little more clear sound stages. AES 16 sound more soft that the USB. For a long time listening, AES 16 may be better.
I try to add Bigben as a external clock for my AES 16. But I do not do that. I just input the AES to Bigben and output from AES and
convert to BNC to my D2. Suddently, I sound more clear sound stage, more deep, more space information. and more soft sound.
The soft here means nature, it means that just like you listen some sound in the real world, it is soft, no may you feel uncomfirtable.
The sound is more accurate position that the USB input, more nature. For USB input, you can here each instructment's positions clearly.
But with Bigben, you are not only hear that, but also here some detail of the instructments. The USB, I must said that it is very detail, but
the detail is still not enougth to make the sound smooth. With the Bigben, you can listen more and more detial, all detail is continuious to
make the sound feel smooth.
D2's USB is good enougth, it is close to AES16 sound card without Bigben. An AES16 will take about 800 dollar, and it is a internal card,
not convinens as a externel card or USB interface.
But, my exprience with BigBen to make me know that it is not the best digital interface. AES16 + Bigben is better. A/B test will make it
obvious. Without A/B, USB is good enougth. D2 is really good DAC. I am happy with it.