Since when is the output impedance of a CD player an issue? Sure, they might use crap opamps, but those can still drive any cable they like, as if cable impedance is a big problem for a line-level load $400 of snake oil. I wonder what the plate voltage is
that's kinda like this CD player tweak I found where you add an RCA plug with a 75ohm resistor soldered to it's tip/shield. And then you just plug it into the S/PDIF port. Haven't had a chance to try it though. http://diyparadise.com/75ohmtweak.htm