I use the 851N as a streamer from ripped files, Spotify, and mostly as DAC for my Marantz 8003 CD player. Initially I used it as a preamp and noticed an improvement when I added a Nordost Vishnu Peter cord. When I first got it I had a Nuforce preamp—the851N sounded the same or better without the preamp, so I got rid of it. I used Heimdall II XLR ICs to connect to Bel Canto ref500 monoblocks. Dali Mentor 6 speakers. I’m going to add video so I recently acquired a Marant 8801 prepro, and tried it out as a preamp this week. To my surprise, there was a clear improvement in soundstaging, bass and details. Not crazy better but clearly better. I’m a big fan of the 851n still, but will keep the Marantz as pre.