Tried it, and it did not work. Active or passive hubs had no effect on the noise whatsoever. My theory is that much of the noise I was getting was from the USB implementation itself, which coupled itself into the ground. The ground loop isolators like the ifi Defender+ might have done the trick, but that was just too expensive for me to just throw money at without trying something more clever first. I spent zero dollars, and placed some tape over the 5v and ground pins on the USB cable, and the noise was eliminated, confirming it was coupled to the power/ground. BTW, I tried isolating the power and ground pins independently by masking them off one at a time, and that also did not work to abate the noise. I had to mask off BOTH of them, noise gone.
My DAC is the LA-QXD1 which also gets its power from a 5V DC adapter, but it still had noise, so it appears the USB noise was making its way into the DAC and interfering with the DAC's power stage, causing the noise. This could theoretically affect any DAC, even yours, which are self powered. Nothing a little electrical tape can't fix! For the Behringer, yeah, the ifi Defender or a separate ground lift + power isolator should do the trick!