Upgrade from Pi3b+ / HifiBerry DAC+ to which DAC?

[hifinet]

I have used the HiFiBerry DAC Pro in the past, and the Allo Boss sounds significantly better. Especially the bass, blacker background and less distortion. The SMSL Sanskrit MkII is in another league from the Boss. The Boss sounds slightly "fuzzy" by comparison. Instrument placement in space and soundstage is much better defined with the SMSL. Each orchestral section has better definition. SINAD is not even close at 97 dB for the Boss and 114 dB for the SMSL. That's when I knew it was time to upgrade. I just got the SMSL a few days ago, with only a couple of listening sessions. It took less than 5 minutes to decide the SMSL was clearly better. The most distinctive difference is "fuzziness" of the Boss. The Boss may have better bass in my system. It's directly driving an Icepower 500ASP Class D amp, which has fairly low input impedence of around 8k . One of TIs advertising points of the PCM5122 is that it has a low output impedence of 1k. Not sure about the output impedence of the SMSL. I will listen to the SMSL for about a week, and then go back to the Boss. I'm with Hans B that it's better to take it slow, listen for a while, before switching back. Better than immediate A/B switches.