This dongle is really something. I recently ABed it with Paw 6000, trying both their 4.4mm output. It is less warm than Paw 6000 at its default setting (using UAPP bit perfect on Samsung S9). Paw 6000 has several DAC filters but it is still warmer at its least warm filter. I prefered S1 to 6000. S1 is slightly less laidback sounding, and matches very well with my QDC 8CL. Pretty detailed, Thick enough to satisfy, Airy enough to prevent it from being congested sounding. Also preferred it to DAPs Cayin N6ii, Opus #2, DX160, DX220 (default), R5, Shanling M0 and dongles Sonata HD Pro, Meizu Pro, Apple dongle, E1DA G3, BTR5. I could see it sapping my phone's battery more than I hope for, but I took the dive and ordered one =)