I did have trouble distinguishing between Opus 320 and DSD converted to PCM, using the ABX in foobar2000. But funny enough the Prd mode on the D-6 is slightly softer than the Pr0 mode. Yet I prefer it, smoother, more detailed and refined. At least that's what I hear in my room, don't care if it's placebo because it sounds incredible anyways. I'm enjoying the hell out of it, it's been many days of great pleasure.It's highly likely you'd never be able to tell a difference with DSD playback using the D-6 or E70V when properly level matched in a controlled test.
Not only that, I have 16bit/44kHz master recordings that absolutely spank many DSD masters in my collection. I don't look for a particular technology used in the recording, I just want the best recorded master whatever the format.
Regardless, just enjoy the D-6. It's a nice DAC for the money.
Yes some DSD mastering is lackluster, I'm thinking of some of MFSL's recent efforts. But some Analogue Productions and SHM-SACDs are spectacular. I'm listening to this Art Pepper Meets the Rhythm Section and wow it sounds good. So involving, smooth, detailed, everything I like. Art Pepper's beautiful alto is recreated so realistically he's in the room with me, a wonderful sensation. The D-6 is a super bargain and I love it.