This thread is like a pin ball machine and considering our collective lack of digital design knowledge most everybody still has relevant input. Are we not all chomping at the bit for all this digital dodox to get worked out? I know I am, enjoying the unbelievable convenience of my Squeezebox without a DAC. My ears aren't bleeding but something needs to be done.
Even with a $1000 budget you just know the technology will soon render your purchase outdated within a year or so. It's like lighting a Roi Tan cigar with a hundred dollar bill. By the same token we're confident we're not going to find a speaker that sounds like a Magico for a grand.
What I've learned from a designer (subjectively? I don't have a clue, but anyway): That much of what's offered is simply a trial and error assemblage of parts with the possibly that a designers strong suit such as power supplies may give his design a slightly different presentation.
USB is not the ideal method of connectivity nor is anything else being used so far. We now have multiple iterations of software that have been written onto the TI TAS1021 chipset in a few short months which took Wavelengths Gordon Rankin years to complete, further clouding the term and quality of what asynchronous USB actually is. Along with the escalating sampling rates we're being hoodwinked with buzz words and figures as we were with low distortion figures back in the seventies. What is Thunderbolt?
The relationship between the converter chipset and the filtering being implemented is where a large part of the sonic correctness can come from in a DAC design yet this has become a forgone area of comparison in both the press and the manufactures white papers. Last month I heard a ripped 16/41kHz CD via a modified six year old DAC compared with a well known multi component conversion/clocking system playing the same music that was now a high sampled HD Track and the old setup simply sound noticeably better. I also heard a modified Benchmark against a much newer stock unit. The 6 Moons review of this comparison is spot on. Parts and smarts.
It seems to me that there is this huge scramble to get a products connectivity and sampling rate up to date while sonic correctness is taking a back seat at the moment. And, none of what I've written above does anything to answer the original posters simple question. On the contrary, I've simply piled on more skepticism forcing us to rely on the audio press who's limited experience and knowledge in this budding aspect of our hobby can be nothing more than a crap shoot. re. Stereophile's recent account of the Rega DAC by a confessed digitally challenged writer. Maybe less knowledge is more and that Rega is a terrific sub $1K DAC.