Thank you very much for your kind words!Great review Ichos! I found the imaging technicalities of the DAC pretty amazing with my speaker setup using the hotter output. May be worth a try for you.
The Fifteen is capable of some pretty amazing pairings when used as an AIO for headphones. It carved through my inventory of headphones with great performance. HD650(M), 660S, Ether CX & K712 all were driven to their fullest. When gaming there is a nice bloom to the bass that is also very precise with pinpoint accuracy in staging. I've not heard an amp before that does both of these things together so well. Usually the staging gets compressed or the sound is more bloomy. Not so with the Fifteen. Really awesome stuff. When I tried external amps I always came back to the built in one. The evolution of current mode is no joke and it really is a unique and very performant sound.
I really found the imaging very accurate both in headphone and DAC modes.
In DAC mode though it couldn't follow some other dedicated bad boys in holography and layering.
Still good and excellent as all-in-one device with headphones.
It matched well with everything I have tried.