El Cheapo AliExpress USB Audio Interface

[k brown]

Yay - replacement arrived; works perfectly.

Turns out most of the noise issue was due to running both a Focusrite interface off FW, and the Q-12 off USB simultaneously. If I power it off a separate supply, all is well.

First unit still had defective input 1 and HP jack.

 

[Yash]

This unit is plastic. Units like the UMC202HD are substantial metal structures -- and have up to 192KHz 24 bit resolution.

Yes, the UMC202HD has metal, but just don't expect the unit to be well-shielded because of that. I hacked mine quite extensively for doing measurements.