girando per il blog di nwavguy sono incappato in questo
VIRTUAL GROUNDS: It would seem the E10, unlike the Mini3 clone E11, does not use a virtual ground. This makes sense because the virtual ground in the E11 prevents using the USB charging port while using it due to the potential severe ground conflicts. The E10, being entirely USB powered, has to operate connected to the PC’s ground. That said, when I connected the E10 to my grounded Agilent scope it freaked out and had massive DC offset. So while there’s no DC voltage between the USB ground and the input or output audio grounds, the E10 seems sensitive to ground loops. Use extreme caution when using it with grounded equipment.
il mio budget è di 200 euro circa, pensavo al vdac2, secondo voi quale dac vedreste meglio con la mia cuffia? un dac dal carattere più dolce o magari "meno dolce"?