Just a quick follow up...I tested my SAP-II connected to my computer's headphone jack which is backed up by a Realtek ALC 889 DAC (which is supposed to be pretty good for onboard audio) and compared it to my DAC X6 connected via USB. I listed to FLAC files via Foobar 2000 with my HiFiMan HE-4XX. DAC X6 to me was a clear winner; lush, richer sound, better separation, tighter bass. The ALC 889 with SAP-II was a bit hot on the top end and quickly fatiguing. Inner details like sound dissipating after the initial hit aren't present. This is not so much a strike against the SAP-II as it is just amplifying the source; actually highlighting issues with the onboard DAC. While the DAC X6 doesn't measure as well as other external DACs, it is a step above onboard audio. As far as amplification goes, it seems to me they are in the same ballpark.