Are you listening to these unamped? It's not surprising that the DT 1990 wouldn't sound as good out of an iPhone/iPad without an amp... Also not surprising that the Andromeda doesn't sound great out of your PC. I don't think I have any amps that could drive both a sensitive IEM and the Beyers satisfactorily.
Anyway. Glad you're enjoying both of your 'phones now!
I tried both with the Sonata HD Cable.
So, after further tests I can confirm that the Andromeda sounds just better then the DT 1990 on the iPhone / iPad with the Sonata HD Cable and not. On the other side, on PC the Andromeda sounds just bad – because of the impedance.