Douk + Ifi xDSD Gryphon
On receiving the Douk U2Pro a few weeks back, I inserted it in between my Phone(s) (Samsung & Iphone) and my Ifi Gryphon xDSD (previously it was USB from phone to Gryphon), connecting via toslink into the Gryphon. The Douk is powered either via portable battery bank or a spare USB socket in my car. Music source is Tidal, either streamed via USB Audio Player Pro on the Samsung, or downloaded Tidal content on both.
The lift in performance - for both phones/all Tidal sources - is not subtle. It gives a great lift* to the sound, in terms of improvements to soundstaging and naturalness of note edges and decay in particular, but also micro and macro-dynamics and bass weight - and this is through my VW car stereo! Let alone through my Sennheiser or Hifiman headphones. It shows me that a fair bit of the raw capability of the Gryphon DAC and amp/line-out was untapped (I'd say 30-40%*) - fed via its USB input at least. I guess its USB section and reclocking/dejittering capability was understandably constrained given its price-point and physical dimensions. The combo now sounds far better than any quasi-portable rig or car stereo has any right to. The Douk has to be the best USD65 I've spent on audio.
@iFi audio - if you've not already done so with the Gryphon with the Douk or other DDCs, try it, it's quite an eye opener. Now if you could create a DDC in a compact form factor with rounded edges and a in-built battery for sub-USD250 I'd be in line...
*Edit- I initially wrote 'night and day' and 50% untapped potential/improvement etc, running from memory, then after a quick AB on my Hifiman HE400i's started second guessing myself, so moderated it a little to what I've written above. But on sustained listening and AB'ing across a range of music over the last half-hour, I think I was right first time. The addition of the Douk lifts the Gryphon into a completely different class.