UR12 not loud enough - louder with power supply?

Hi,

today I have received my Steinberg UR12 together with a Rode NT1.

Though, when direct monitorin is turned on, the output to my headphones is not loud enough.
Because of that, also the monitoring is not loud enough.

From what I have read about the UR22 this will maybe get better when using a power supply instead of power through usb.
Is that true?

Or is there any other way to help with this problem?

Best regards

Which headphone are you using? The UR12 is not able to drive high-impedance headphones at high volume. (Nor is any other USB-powered device, actually.)