The interior of most PCs (and phones) are very noisy from an RF standpoint. I get hiss on my USB headphones (!!!) from just out poorly shielded the case on my computer is.
That said, Apple had traditionally put very well isolated low noise DACs in their products. I'm not sure if that is still the case.
Isn't the story that they don't put any DACs in their products anymore? Or, more accurately, that the DACs have moved to the output devices (headphones, speakers).
That said, Apple had traditionally put very well isolated low noise DACs in their products. I'm not sure if that is still the case.