Yeah, there's a line-level switch on the thing. In one position, I get no results whatsoever, and in the other, I get the above results. Also, yeah, the PlainTalk microphone plug is longer than the standard ones you see on normal PC microphones and such... but as I recall, I think the packaging said something about actually being able to use the PlainTalk mic... (or maybe I'm just going nuts) but yeah, only one channel with my plaintalk mic with the long plug, which kinda sticks out about half a cm...
And now I just tried it with one of the really Old-School Apple Microphones... the precursor to the Plaintalk, the one with a standard size plug, which looks like a little smoke detector with a wire sticking out of it. Same results. one channel using same switch position.
I could just be an odd case, though... which is why I'm hoping SOMEone else got one and has good results...