Coming up on a full week so far, using other amps as well such as the iBasso PB3, and Ray Samuels Intruder. Kind of running the gamut.
The RS Intruder is a completely different level, so suffice to say it is a monster, even after several years in production. Just wow. I will hate to give it back. Best by far of the three.
Regarding the PB3, I made a dedicated purchase as it was a balanced out amp. And affordable. It is a very good amp at +/-$230. So far, slightly behind the iFi.
As for the xDSD? I have mainly run BT through my Opus#2 and Shanling M3s. What the iFi provides to the M3s is more definitive, “cleaning up” of the sound. It is a bit more crisp sounding with decent extension on both ends. The XBass+ provides much less oomph than my iFi BL, but that is OK. And the 3D is less pronounced than my other iFi items. Again, that is OK. Detail and sound stage are adequate, but not noticeably better than without (to me).
Through the Opus, the benefits are much smaller if at all noticeable to my bad ears. The Opus is a stellar example as is, and hard to improve upon.
Running the xDSD through my MBP, and the blue USB cable there is a DEFINITE improvement in the overall quality of sound. Fuller, deeper reaching bass, and very good sound stage highlight what I hear. Take that with a grain, and my review will posit more findings.
I will state that to me, the overall sound is better overall with a more full, more detailed and wider of sound stage sound when using the USB cable instead of BT. I am not versed enough to tell why…yet.
This is a very nice little critter with some possibilities I am still working out, and loath to mention until I try them.
Hope this helps. Cheers.