Well I received I received the DAC-1 yesterday and initial impressions are good.
Build quality is superb, heavy, sturdy, really a nice piece visually.
The USB DAC section is a huge improvement over the Schiit Modi that it is replacing. Bigger soundstage, better separation, vocals (especially female) are clearer. 99% of my music is CD-lossless rips, some HD Tracks, and I stream from Tidal (which is fantastic by the way), so I have just begun downloading some sample DSD files and enjoyed that for the first time last night. Not that I want to start spending money on that....but I will be selective in which albums to download.
The good but not great. HP OUT: While my selection of headphones are modest I felt right away that while there was improvement over the integrated amp, NAD C375, but I did not really think it was a giant leap forward in sound quality or power. HE-400 in high gain mode had plenty of power. I would say marginal improvement. I am still burning it in and will hold final impressions to a later date.
The okay: Playing CD's through my Marantz CD6004 via RCA to the IA and via Coax the DAC-1. No discernible difference. Sounded exactly the same. I almost suspected that as the CD6004 has many of the same internals as the DAC-1 but frankly I wished for more (or new). Definitely the Marantz "house" sound. Smooth and musical.
The bad: I thought I'd give the preamp section a try and plugged the DAC-1 into the main in on the integrated amp. Right away everything felt short, volume control needed to go to 12 to 2 just to get to a reasonable volume level and even then it did not sound as good as the IA by itself.
I'll update this post over the weekend when I have more time with it.
I also ordered the OPPO HA-1 which should arrive tomorrow ( i hope ) so it will be interesting comparing the two over the weekend.