ANY Musical Fidelity V-DAC MKII owners? Problems..

Just pick the V-DAC II from my local hifi shop yesterday. It sounds very good, way way better than my old Denon AVD2000 preamp as a DAC.

BUT there is a problem. When using either SPDIF or COAXIAL, then turn the toggle switch to USB (when the USB port is not connected, or connected but the computer is turned off), the speaker will produce constant POP click noise, never stop.

All the three input works fine by its own, only the above problem.

I don't think it is normal. Am I right? Any one has experienced this problem?
What is the purpose of switching to usb if nothing is connected or connecting it with the computer turned off? The pop noise is the dac looking to lock on to the oncoming signal of which there is none.
Agree searching out a non problem then worrying about it is not really a problem.
Get over it.
from time to time I get the same clicking sound with the v-link192,in my case usb cable was defective,probably inside usb cable wire is loose