What is galvanic isolation on the DAC's USB input? | Wyred 4 Sound

What is galvanic isolation on the DAC's USB input?

For all of our DACs except original DAC-1 and DAC-2, we feature an improved USB input that has galvanic isolation. What this means is that the USB input is much quieter than a standard USB input. There are also regulators that filter the power from your computer's USB output.

Note: the galvanically isolated USB input is NOT self-powered; it relies on your computer's USB output for power.