UPDATE: well, i returned it (Amazon) & re-purchased the same thing (thru a different Amazon seller); got it today, plugged it in, and the same exact problem.
i’ll start a new thread topic since this is off-topic of my original questions. but wanted to give a quick update, since you all have been so kind & helpful.
in case you’re interested, it’s @ Signal Passing Through Audio Interface When Knobs Are At Zero