MIDI sounds from my GR-33.
there's no such thing as a "midi sound" midi is a symbolic language, like the text your reading. When I type
I'm counting on you to to the work of imagining a dog. If I sent you a jpg of a dog, that's less symbolic, if I mailed you a real dog... well you get the idea. MIDI carries only information about when, how loud and what pitch a note is. The only actual "sound" (in the form of an alternating current) comes from the audio outputs, which will have to be mixed (I know the mix outs of the gr-30 do this) with your guitar sound, but you've got to plug your guitar output into the gk2A for this to work.
Hope this helps,