USB Isolation
USB isolation separates parts of the USB audio connection electrically while still passing data. Galvanic isolation breaks a direct conductive path. Optical isolation carries information across the barrier using light, and can provide galvanic isolation too.
An optical barrier can be inside the equipment: the label does not require an external optical socket. These descriptions identify how a connection is isolated, rather than ranking its sound quality.
USB Isolation — Streamer
On a streamer, look for isolation of the USB audio output feeding an external DAC (digital-to-analogue converter). If the streamer also accepts computer audio through a USB input, isolation of that input counts too. Check which port the description covers.
An isolated network port, power supply or analogue stage does not establish USB isolation. Neither does a switchable USB power line, or a USB output described only as low-noise or reclocked. Missing documentation leaves isolation unknown, not confirmed absent.
Sources
- CN0550 USB 2.0 isolator reference design — Analog Devices
- Breaking ground loops with functional isolation — Analog Devices
USB Isolation — DAC
On a DAC, this describes isolation of the USB input or its receiver path from the conversion circuitry. Breaking the USB ground-current path can prevent interference circulating through multiple ground connections, called a ground loop.
The benefit depends on the interference and the system; better sound is not guaranteed. Check the isolated connection’s supported USB speed, audio formats and sample rates, and whether its power provision meets the connected device’s requirements. Isolation alone confirms none of these capabilities.
Sources
- CN0550 USB 2.0 isolator reference design — Analog Devices
- Breaking ground loops with functional isolation — Analog Devices
Sources
- Isolation and iCoupler technology FAQ — Analog Devices