Ok, since at least 2 people wanted it and I have the brick as well as Hypsos I've spent the morning A/B ing.
Test track : The Cranberies - Zombie
Bass + Dynamics : Similar between both PSUs
Midrange :
Brick : Relatively decent space and clarity, better and more natural sounding than Gustard X26 Pro that I've had some time ago. Nowhere near the refinement and space of May. (both references to other DACs from memory, but I did spend considerable amount of time comparing both of those DACs b2b as well as Wanda b2b May so it's not completely from memory either)
Hypsos : considerable improvement in clarity, depth, relaxation and ease of tone. It's still not May level of midrange refinement but it's close IMO. It beats May on clarity though, so it's not flat out inferior ... but in general May wins with even more ease and refinement.
Treble :
Brick : Cheap, flat, horrible. Sounds like a typical cheap delta sigma DAC with no refinement, no space, and harsh, tone is terrible. It really kills everything Wandla had going for it in Midrange and Bass. Gustard X26 Pro had considerably cleaner and more refined treble even if it wasn't a lot more spacious, so this is seriously bad.
Hypsos : Total 180 of the treble performance. Clear, clean, very refined, very spacious. Miles better than Gustard and for me (I can see people with pitchforks at my doorstep lol) better than May which can be a little bit too dull in comparison. Wandla + Hypsos has 90% of the refinement but it's got more leading edge, more presence, and more freshness, resulting in a taller and more clearly defined stage. This is not massively better than May, of course, and it is subjective, but to me, at the very least it's not outclassed by May.
Conclusion :
Test track sounds like a cheap toy from the brick PSU compared to the Hypsos. The cymbals sound like a cheap synthesiser losing any sense of space, air authenticity, not to mention refinement. If the treble was better (it would have to be miles better tho) on the brick, maybe Hypsos wouldn't be that easy to justify, but if you have a system that has good treble extension and refinement, then Wandla with brick PSU will sound like
and Hypsos is pretty much a must. And if you don't have a system like that, then there's no point in spending 2800 euro on Wandla anyway IMO, any other DAC will do the job just fine.
I would even go as far as saying that I'm surprised Ferrum offers Wandla without Hypsos, because the difference is incredible, going from trash, to really high class of refinement. I'm actually shocked at how rubbish the brick sounds, I didn't expect much from it but I was certain it would sound better than Gustard X26 Pro ... well ... it doesn't, Gustard in comparison to Wandla with brick sounds like a king of refinement ...
Obv system synergy etc. YMMV and those are just ramblings of one guy who probably spent too much on audio anyway
Update: for the sake of completeness I also tested the brick psu with power conditioning, it helped to clear the cluttered treble and harshness a bit, but not enough to make Wandla with brick perform better than the Gustard which is considerably less expensive.