Just collected my HP-A4 this afternoon!

Sorry for the delay as I
I'll just post some brief impressions:
Build
The set looks very beautiful. I don't think I've seen many other DAC/AMP that has such a nice design.
There's only a slight problem with the workmanship of the back panel. The ports are not straight, but it's just a very very minor problem. (Go google for images)
They do provide 4 rubber feet for you to paste at the bottom of the unit.
Sound
Laptop (Foobar2000 WASAPI) > Fostex HP-A4 > Audio Technica ATH-ES10
Laptop (Foobar2000 WASAPI) > Fostex HP-A4 > Audio Technica ATH-ESW11LTD
Laptop (Foobar2000 WASAPI) > Fostex HP-A4 > Audio Technica ATH-A900XLTD
I've still not spent a lot of time on the set yet and I also have nothing to compare the HP-A4 with so please take this part with a pinch of salt. (Sold my ODAC+O2 back in December. Continental V3 has been on RMA for many months, returning end of this month)
Tried the HP-A4 with quite a few headphones. The amp section isn't really powerful (As expected from the USB). It didn't manage to drive the Alpha Dogs and Beyerdynamic DT880 Pro 250Ohms. But it's surprisingly quite decent for a USB powered amp. Managed to drive quite a number of full-sized headphones (like the ATH-AD2000X).
Personally I feel that the great part of the HP-A4 is actually the DAC rather than the AMP. Didn't manage to test out the line out yet. Would post impressions when I get the chance to.
I compared the stock cable with the ALO The Green Line USB. I can say that the stock cable is already pretty decent. Personally didn't like the ALO cable with the HP-A4, it kind of made the midrange not as engaging.
There's a digital filter setting on the set to change between a fast or slow roll off. So far didn't manage to hear any difference yet.
Can't really talk about the sound as I have nothing to compare against, but here are some very brief impressions. (I listen to mainly Asian music: Japanese, Korean, Chinese) I'd say that the sound is clear, transparent but musical.
I'm also thinking of trying the set with a USB power conditioner like the iUSB, but didn't have the time to try today. Would try another time.
Conclusion
I don't really have much to conclude yet. But the price is pretty decent for the sound.
I'll see if I have time in the coming weeks to do a proper review/impressions. Now have to go back to assignments.
If you have any question just let me know, I'll try my best to answer them.
