JerryLeedsMy SMSL T1 draws 0.43Amps whatever volume and headphones I use Hifiman HE350, HE400i, Edition X v2, Audeze LCD2 and LCD3 and Shure 1540. I have only tested it with the USB input.
Simple math (24V x 0.43A) indicates that about 10.5 Watts is minimum. My 25W Nobsound gives the SMSL T1 a real upgrade. Sound stage is bigger, more details, more bass, tighter mid and treble is more precise. I can also hear more details and less noise.
BTW: Using a Telefunken E88CC from the 1960s.
KristianNI have now tested with "line in". Draws 0.37 Amps.
This time I use a Schiit Mani (with another LPS) and my fathers ERA mk4 turntable with a SME 3009 arm. Vinyl sounds pretty good :-)