What is your budget range for amp, dac, or combined?   The D100 MKII is one of the best dac/amp devices in the sub $500 category. Below $1k there might be something better already...

You can check these two threads and see what people say about these DACs:   M-Dac Thread   Wadia 121 Thread

Quote:  I've read somewhere that they saved the USB input to achieve the low price and focus on sound quality.   You can add a M2Tech Hiface Two and you have a high-end 192kHz/24bits USB input on the D18 

I have not heard this dac but if I had to decide for one below $500 right now it would be the Yulong D100 for sure!   Review here   And Review of the newer MKII Model here     I believe that is as best as you can get with $500   Cheers

Oh well.. the communication went a bit wrong there i guess...    But yea, i don't think the M-Dac lacks in the dynamic department. And have never heard anyone else saying that....  

M-DAC alternatives:   Yulong D100, Matrix Mini-I, Audio-gd NFB-5, DacMagic Plus and the Asus Xonar Essence One come to my mind. All of them sub-$500 apart from the last two.

Suggestion: Behringer DEQ2496:   http://www.behringer.com/EN/Products/DEQ2496.aspx   Or DEQ1024:   http://www.behringer.com/EN/Products/DEQ1024.aspx   I believe they do the signal processing digitally though...

I'm not sure about non-upsampling and the ASIO/WASAPI drivers since i use a Mac but my suggestion would be the Audiolab M-DAC.   It has async USB 96/24, Toslink & SPDIF inputs, balanced & RCA outputs, fixed/variable selectable and a good headphone amp and not lacking in bass...   Volume...

Interesting comparison.   I really love the detailed, in your face sound of the M-DAC. But then again i haven't had a chance yet to experience other dacs in that price-range.   Is it fatiguing? I don't know, i can listen for hours, but it is certainly so detailed and attention-grabbing...

I considered one of these for my 2nd rig at work but was holding off due to the lack of reviews.   And they had a good sale in their ebay store till the end of july. But even for the normal price it sounds like a keeper..    I love that i has a 1/4" jack, not very common for small devices.

Here are the google-translated specs from the matrix site, haven't found a review anywhere yet.       Source: http://www.matrix-digi.com/english/cpshow.asp?pid=36