I did not compare them in the same setup. I used the DA8 with USB input from the traditional "burn-in" process, for few days.
I am now using the DA8 fed by the Ciunas Converter (coax) with the A18. The bass is more extended, treble is less raw but this could be due to the Ciunas being better than the DA8's USB input.
I didn't feel like I was missing a lot from the DA8's internal headphone amp, honestly. It has no particular flaws that I could notice.
The A18 sounds bigger and more extended (keeping in mind the Ciunas thing), which is the typical improvement with better quality gear. It sounds warmer, too.
Thank you again for your prompt answer.
I am thinking about USB external power supply (AqVox USB external power supply) and a USB/AES-EBU Yellowtec PUC2 Lite Converter known to be a bargain in Europe for the price according to Roberto2...
Macbook Pro early 2011 16 Go RAM-->USB link (with AqVox power supply)-->Yellowtec PUC2 lite-->AES/EBU Yulong discret AZP OPAs DA8-->Hifiman HE-560 Headphones for recording tracks up to 192KHz rates.
Edited by teiki arii - 5/13/14 at 1:06pm