I stand corrected (on the Song Audio issue). Thanks.
EDIT to add a couple more comments...
I'm listening to it now and somehow it's picking up a radio station! I can hear it faintly in the background. If I move the preamp around, the background sound gets louder or quieter but never quite goes away entirely.
Also can't completely eliminate the previously-mentioned hum.
If this keeps up I will have to judge it "not acceptable". YMMV.
ANOTHER EDIT: When I set this up initially, I used my "best" interconnect cables, some old Audioquest FMS Blue. On a whim I replaced them with some generic interconnect that looks decent, at least has gold-plated connectors. Guess what: No more radio station, and hum is 99% gone now. Wonder what the deal is with the other cables?
Sorry this is sort of a stream-of-consciousness "review". By the time this is over I'll have no credibility left.
I'm feeling a little more optimistic now.