The D-1 is going to be limited going through an integrated amp like the CSiB (I owned it). I say this because the most resolving preamp I have heard is the Benchmark LA4/HPA4 and when I connected the still breaking in D-1 into it the sound was not particularly outstanding. It was better than the Schiit Singular DAC I also had on the preamp (both by XLR) but not by much., However, I was told by my friend, Danny who sells this thing, to go direct to amp because the designer told him that was the best way to hear the difference of the D-1 compared to other DACs.
When put the D-1 directly into my CODA #16 amp and Yamaha NS5000 speakers the improvement in resolution was immediately evident. I put my HPA4 up for sale the next day. I have owned the LA4 or HPA4 since about 2012 and have heard it with many amps and sources. It was never the weak link until the D-1.
I sold my CODA #16 last week (still pending) and I will be using the D-1 with my CODA #11 amp and my Class D Audio GanFet 6.5 amp. Both have XLR and RCA inputs on the amp. I use XLR from the D-1 into either amp. I have a long Benchmark XLR cable to the Livingroom. I will only listen to the D-1 on my best system.
On my office system, Magnepan Mini + GanFet 6.5, I also have a Schiit Valhalla 3 OTL/OCL tube preamp + audiophile RCA switch to listen to 2 tuners and an RME DAC (for SACD's). The Valhalla 3 goes into the GanFet amp by RCA. The nice thing about the GanFet is that it automatically switches between RCA and XLR.
None of this is particularly convenient but the sonic difference of the D-1 makes it worthwhile for me.

