Definitely an improvement with my Chord Qutest when using with a linear power supply over the power from my iMac. Smoother mids & highs and no hash or artefacts. The Qutest requires constant 5V power to its USB port.
If your DAC only requires power for the initial USB handshake like my Topping D70, you can use any outside power source to make the connection then disconnect the power to this adapter after startup and leave the adapter in place, it will then only get data from your computer or other source.
Highly recommended!