Got home tonight and discovered that the patch cable on the input side of my modular was laying across the power supply of the unit below it in the rack--and I had hope. However, no matter how I moved the cables around, the Wasp continued its -20 dB hiss.
I finally removed all the cables, both input and output, and put a probe on the output jack. Sure enough, the hiss is still there, so that tells me that the source of the problem is the uZeus. My other module (A-136 Dis) exhibits the similar behavior at a much lower audio level, so based on the tech sheet you provided, I feel like the Wasp is just more susceptible to these kinds of things.
So for now, I think I will just EQ out the hiss until I'm ready to upgrade to a cleaner power supply. I'll have to listen to it if I'm monitoring from the rack, but at least it will be inaudible when the audio reaches my DAW.
Thanks for all your help!